ELAV/HuD family splicing factor; This model describes the ELAV/HuD subfamily of splicing factors found in metazoa. HuD stands for the human paraneoplastic encephalomyelitis antigen D of which there are 4 variants in human. ELAV stnds for the Drosophila Embryonic lethal abnormal visual protein. ELAV-like splicing factors are also known in human as HuB (ELAV-like protein 2), HuC (ELAV-like protein 3, Paraneoplastic cerebellar degeneration-associated antigen) and HuR (ELAV-like protein 1). These genes are most closely related to the sex-lethal subfamily of splicing factors found in Dipteran insects (TIGR01659). These proteins contain 3 RNA-recognition motifs (rrm: pfam00076).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFkgyeGSLIklTSK----------QPVGFVSFDSRSEAEAAKNALNGirfdpEIPqtlr 95
Cdd:TIGR01661  92 LYVSGLPKTMTQHELESIFSPF----GQII--TSRilsdnvtglsKGVGFIRFDKRDEADRAIKTLNG-----TTP---- 156

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  96 lefaKANTKMAKNKLVGTPNPSTP--LPNTVPQFIArePYELTVPALYPSSPEVWAPYplypAELAPALPPPAFTYPASL 173
Cdd:TIGR01661 157 ----SGCTEPITVKFANNPSSSNSkgLLSQLEAVQN--PQTTRVPLSTILTAAGIGPM----HHAAARFRPSAGDFTAVL 226

                         170
                  ....*....|....*..
gi 2462617419 174 HAQVSSPPPAMGALCPR 190
Cdd:TIGR01661 227 AHQQQQHAVAQQHAAQR 243

RNA recognition motif. (a.k.a. RRM, RBD, or RNP domain); The RRM motif is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteriztic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFKGYEG-SLIKLTSKQP--VGFVSFDSRSEAEAAKNALNGIRFD 87
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSiRLVRDETGRSkgFAFVEFEDEEDAEKAIEALNGKELG 65

ELAV/HuD family splicing factor; This model describes the ELAV/HuD subfamily of splicing factors found in metazoa. HuD stands for the human paraneoplastic encephalomyelitis antigen D of which there are 4 variants in human. ELAV stnds for the Drosophila Embryonic lethal abnormal visual protein. ELAV-like splicing factors are also known in human as HuB (ELAV-like protein 2), HuC (ELAV-like protein 3, Paraneoplastic cerebellar degeneration-associated antigen) and HuR (ELAV-like protein 1). These genes are most closely related to the sex-lethal subfamily of splicing factors found in Dipteran insects (TIGR01659). These proteins contain 3 RNA-recognition motifs (rrm: pfam00076).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFkgyeGSLIklTSK----------QPVGFVSFDSRSEAEAAKNALNGirfdpEIPqtlr 95
Cdd:TIGR01661  92 LYVSGLPKTMTQHELESIFSPF----GQII--TSRilsdnvtglsKGVGFIRFDKRDEADRAIKTLNG-----TTP---- 156

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  96 lefaKANTKMAKNKLVGTPNPSTP--LPNTVPQFIArePYELTVPALYPSSPEVWAPYplypAELAPALPPPAFTYPASL 173
Cdd:TIGR01661 157 ----SGCTEPITVKFANNPSSSNSkgLLSQLEAVQN--PQTTRVPLSTILTAAGIGPM----HHAAARFRPSAGDFTAVL 226

                         170
                  ....*....|....*..
gi 2462617419 174 HAQVSSPPPAMGALCPR 190
Cdd:TIGR01661 227 AHQQQQHAVAQQHAAQR 243

sex-lethal family splicing factor; This model describes the sex-lethal family of splicing factors found in Dipteran insects. The sex-lethal phenotype, however, may be limited to the Melanogasters and closely related species. In Drosophila the protein acts as an inhibitor of splicing. This subfamily is most closely related to the ELAV/HUD subfamily of splicing factors (TIGR01661).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFKGYEGSLIKLTSKQ----PVGFVSFDSRSEAEAAKNALNGI 84
Cdd:TIGR01659 110 LIVNYLPQDMTDRELYALFRTIGPINTCRIMRDYKTgysfGYAFVDFGSEADSQRAIKNLNGI 172

RNA recognition motif (RRM) found in vertebrate RNA-binding protein with multiple splicing 2 (RBP-MS2); This subfamily corresponds to the RRM of RBP-MS2, encoded by RBPMS2 gene, a paralog of RNA-binding protein with multiple splicing (RBP-MS). The biological function of RBP-MS2 remains unclear. Like RBP-MS, RBP-MS2 contains an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2462617419  23 VRTLFVSGLPLDIKPRELYLLFRPFKGYEGSLIKLTSKQPVGFVSFDSRSEAEAAKNALNGIRFDPEIPQTLRLEF 98
Cdd:cd12683     1 VRTLFVSGLPVDIKPRELYLLFRPFKGYEGSLIKLTSKQPVGFVTFDSRAGAEAAKNALNGIRFDPENPQTLRLEF 76

RNA recognition motif (RRM) found in Drosophila couch potato (cpo) coding RNA-binding protein and similar proteins; This subfamily corresponds to the RRM of Cpo, an RNA-binding protein encoded by Drosophila couch potato (cpo) gene. Cpo contains a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). It may control the processing of RNA molecules required for the proper functioning of the peripheral nervous system (PNS).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  23 VRTLFVSGLPLDIKPRELYLLFRPFKGYEGSLIKLTSKQ-----PVGFVSFDSRSEAEAAKNALNGIRFDPEIPQTLRLE 97
Cdd:cd12684     1 VRTLFVSGLPMDAKPRELYLLFRAYKGYEGSLLKVTSKNgkttsPVGFVTFLSRQAAEAAKQDLQGVRFDPDLPQTLRLE 80

                  ...
gi 2462617419  98 FAK 100
Cdd:cd12684    81 FAK 83

RNA recognition motif. (a.k.a. RRM, RBD, or RNP domain); The RRM motif is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteriztic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFKGYEG-SLIKLTSKQP--VGFVSFDSRSEAEAAKNALNGIRFD 87
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSiRLVRDETGRSkgFAFVEFEDEEDAEKAIEALNGKELG 65

RNA recognition motif 2 (RRM2) found in the Hu proteins family; This subfamily corresponds to the RRM2 of Hu proteins family which represents a group of RNA-binding proteins involved in diverse biological processes. Since the Hu proteins share high homology with the Drosophila embryonic lethal abnormal vision (ELAV) protein, the Hu family is sometimes referred to as the ELAV family. Drosophila ELAV is exclusively expressed in neurons and is required for the correct differentiation and survival of neurons in flies. The neuronal members of the Hu family include Hu-antigen B (HuB or ELAV-2 or Hel-N1), Hu-antigen C (HuC or ELAV-3 or PLE21), and Hu-antigen D (HuD or ELAV-4), which play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads. Hu-antigen R (HuR or ELAV-1 or HuA) is the ubiquitously expressed Hu family member. It has a variety of biological functions mostly related to the regulation of cellular response to DNA damage and other types of stress. Moreover, HuR has an anti-apoptotic function during early cell stress response. It binds to mRNAs and enhances the expression of several anti-apoptotic proteins, such as p21waf1, p53, and prothymosin alpha. HuR also has pro-apoptotic function by promoting apoptosis when cell death is unavoidable. Furthermore, HuR may be important in muscle differentiation, adipogenesis, suppression of inflammatory response and modulation of gene expression in response to chronic ethanol exposure and amino acid starvation. Hu proteins perform their cytoplasmic and nuclear molecular functions by coordinately regulating functionally related mRNAs. In the cytoplasm, Hu proteins recognize and bind to AU-rich RNA elements (AREs) in the 3' untranslated regions (UTRs) of certain target mRNAs, such as GAP-43, vascular epithelial growth factor (VEGF), the glucose transporter GLUT1, eotaxin and c-fos, and stabilize those ARE-containing mRNAs. They also bind and regulate the translation of some target mRNAs, such as neurofilament M, GLUT1, and p27. In the nucleus, Hu proteins function as regulators of polyadenylation and alternative splicing. Each Hu protein contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an ARE. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFkgyeGSLIklTSK----------QPVGFVSFDSRSEAEAAKNALNG 83
Cdd:cd12652     3 LYVSGLPKTMTQKELEQLFSQF----GRII--TSRilcdnvtglsRGVGFIRFDKRVEAERAIKALNG 64

RNA recognition motif 2 (RRM2) found in the U1A/U2B"/SNF protein family; This subfamily corresponds to the RRM2 of U1A/U2B"/SNF protein family, containing Drosophila sex determination protein SNF and its two mammalian counterparts, U1 small nuclear ribonucleoprotein A (U1 snRNP A or U1-A or U1A) and U2 small nuclear ribonucleoprotein B" (U2 snRNP B" or U2B"), all of which consist of two RNA recognition motifs (RRMs) connected by a variable, flexible linker. SNF is an RNA-binding protein found in the U1 and U2 snRNPs of Drosophila where it is essential in sex determination and possesses a novel dual RNA binding specificity. SNF binds with high affinity to both Drosophila U1 snRNA stem-loop II (SLII) and U2 snRNA stem-loop IV (SLIV). It can also bind to poly(U) RNA tracts flanking the alternatively spliced Sex-lethal (Sxl) exon, as does Drosophila Sex-lethal protein (SXL). U1A is an RNA-binding protein associated with the U1 snRNP, a small RNA-protein complex involved in pre-mRNA splicing. U1A binds with high affinity and specificity to stem-loop II (SLII) of U1 snRNA. It is predominantly a nuclear protein that shuttles between the nucleus and the cytoplasm independently of interactions with U1 snRNA. Moreover, U1A may be involved in RNA 3'-end processing, specifically cleavage, splicing and polyadenylation, through interacting with a large number of non-snRNP proteins. U2B", initially identified to bind to stem-loop IV (SLIV) at the 3' end of U2 snRNA, is a unique protein that comprises of the U2 snRNP. Additional research indicates U2B" binds to U1 snRNA stem-loop II (SLII) as well and shows no preference for SLIV or SLII on the basis of binding affinity. U2B" does not require an auxiliary protein for binding to RNA and its nuclear transport is independent on U2 snRNA binding.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2462617419  24 RTLFVSGLPLDIKPRELYLLFRPFKGYEGslIKLTSKQPVGFVSFDSRSEAEAAKNALNGIRFDPEIP 91
Cdd:cd12247     3 KILFLQNLPEETTKEMLEMLFNQFPGFKE--VRLVPRRGIAFVEFETEEQATVALQALQGFKITPGHA 68

RNA recognition motif (RRM) found in eukaryotic translation initiation factor 3 subunit G (eIF-3G) and similar proteins; This subfamily corresponds to the RRM of eIF-3G and similar proteins. eIF-3G, also termed eIF-3 subunit 4, or eIF-3-delta, or eIF3-p42, or eIF3-p44, is the RNA-binding subunit of eIF3, a large multisubunit complex that plays a central role in the initiation of translation by binding to the 40 S ribosomal subunit and promoting the binding of methionyl-tRNAi and mRNA. eIF-3G binds 18 S rRNA and beta-globin mRNA, and therefore appears to be a nonspecific RNA-binding protein. eIF-3G is one of the cytosolic targets and interacts with mature apoptosis-inducing factor (AIF). eIF-3G contains one RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). This family also includes yeast eIF3-p33, a homolog of vertebrate eIF-3G, plays an important role in the initiation phase of protein synthesis in yeast. It binds both, mRNA and rRNA, fragments due to an RRM near its C-terminus.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  25 TLFVSGLPLDIKPRELYLLFRPFkgyeGSLIKLT------SKQPVGF--VSFDSRSEAEAAKNALNGIRFDPEIpqtLRL 96
Cdd:cd12408     1 TIRVTNLSEDATEEDLRELFRPF----GPISRVYlakdkeTGQSKGFafVTFETREDAERAIEKLNGFGYDNLI---LSV 73

                  ...
gi 2462617419  97 EFA 99
Cdd:cd12408    74 EWA 76

ELAV/HuD family splicing factor; This model describes the ELAV/HuD subfamily of splicing factors found in metazoa. HuD stands for the human paraneoplastic encephalomyelitis antigen D of which there are 4 variants in human. ELAV stnds for the Drosophila Embryonic lethal abnormal visual protein. ELAV-like splicing factors are also known in human as HuB (ELAV-like protein 2), HuC (ELAV-like protein 3, Paraneoplastic cerebellar degeneration-associated antigen) and HuR (ELAV-like protein 1). These genes are most closely related to the sex-lethal subfamily of splicing factors found in Dipteran insects (TIGR01659). These proteins contain 3 RNA-recognition motifs (rrm: pfam00076).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFkgyeGSLIklTSK----------QPVGFVSFDSRSEAEAAKNALNGirfdpEIPqtlr 95
Cdd:TIGR01661  92 LYVSGLPKTMTQHELESIFSPF----GQII--TSRilsdnvtglsKGVGFIRFDKRDEADRAIKTLNG-----TTP---- 156

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  96 lefaKANTKMAKNKLVGTPNPSTP--LPNTVPQFIArePYELTVPALYPSSPEVWAPYplypAELAPALPPPAFTYPASL 173
Cdd:TIGR01661 157 ----SGCTEPITVKFANNPSSSNSkgLLSQLEAVQN--PQTTRVPLSTILTAAGIGPM----HHAAARFRPSAGDFTAVL 226

                         170
                  ....*....|....*..
gi 2462617419 174 HAQVSSPPPAMGALCPR 190
Cdd:TIGR01661 227 AHQQQQHAVAQQHAAQR 243

polyadenylate binding protein, human types 1, 2, 3, 4 family; These eukaryotic proteins recognize the poly-A of mRNA and consists of four tandem RNA recognition domains at the N-terminus (rrm: pfam00076) followed by a PABP-specific domain (pfam00658) at the C-terminus. The protein is involved in the transport of mRNA's from the nucleus to the cytoplasm. There are four paralogs in Homo sapiens which are expressed in testis, platelets, broadly expressed and of unknown tissue range.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  64 GFVSFDSRSEAEAAKNALNGIRFDPEiP-------------QTLRLEFAKANTKMaknklvgtpnPSTPLPNTVPQFIAR 130
Cdd:TIGR01628 329 GFVCFSNPEEANRAVTEMHGRMLGGK-PlyvalaqrkeqrrAHLQDQFMQLQPRM----------RQLPMGSPMGGAMGQ 397

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419 131 EPYELTVP-ALYPSSPEVWA-----PYPLYP-AELAP-ALPPPAFTYPASLHAQVSSPPPAMGAL------CPRPVLSHL 196
Cdd:TIGR01628 398 PPYYGQGPqQQFNGQPLGWPrmsmmPTPMGPgGPLRPnGLAPMNAVRAPSRNAQNAAQKPPMQPVmyppnyQSLPLSQDL 477

                         170       180
                  ....*....|....*....|....
gi 2462617419 197 SQEGSSNSALCLVSKWIQMHQAMS 220
Cdd:TIGR01628 478 PQPQSTASQGGQNKKLAQVLASAT 501

RNA recognition motif 3 (RRM3) found in CELF/Bruno-like family of RNA binding proteins CELF1, CELF2, CELF3, CELF4, CELF5, CELF6 and similar proteins; This subgroup corresponds to the RRM3 of the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) proteins, a family of structurally related RNA-binding proteins involved in the regulation of pre-mRNA splicing in the nucleus and in the control of mRNA translation and deadenylation in the cytoplasm. The family contains six members: CELF-1 (also termed BRUNOL-2, or CUG-BP1, or NAPOR, or EDEN-BP), CELF-2 (also termed BRUNOL-3, or ETR-3, or CUG-BP2, or NAPOR-2), CELF-3 (also termed BRUNOL-1, or TNRC4, or ETR-1, or CAGH4, or ER DA4), CELF-4 (also termed BRUNOL-4), CELF-5 (also termed BRUNOL-5), CELF-6 (also termed BRUNOL-6). They all contain three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein. The low sequence conservation of the linker region is highly suggestive of a large variety in the co-factors that associate with the various CELF family members. Based on both sequence similarity and function, the CELF family can be divided into two subfamilies, the first containing CELFs 1 and 2, and the second containing CELFs 3, 4, 5, and 6. The different CELF proteins may act through different sites on at least some substrates. Furthermore, CELF proteins may interact with each other in varying combinations to influence alternative splicing in different contexts.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFkGYEGSLIKLTSKQP-----VGFVSFDSRSEAEAAKNALNG 83
Cdd:cd12362     1 LFVYHLPNEFTDQDLYQLFAPF-GNVVSAKVFVDKNTgrskgFGFVSYDNPLSAQAAIKAMNG 62

RNA recognition motif (RRM) found in apoptotic chromatin condensation inducer in the nucleus (acinus) and similar proteins; This subfamily corresponds to the RRM of Acinus, a caspase-3-activated nuclear factor that induces apoptotic chromatin condensation after cleavage by caspase-3 without inducing DNA fragmentation. It is essential for apoptotic chromatin condensation and may also participate in nuclear structural changes occurring in normal cells. Acinus contains a P-loop motif and an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), which indicates Acinus might have ATPase and DNA/RNA-binding activity.

                          10        20        30
                  ....*....|....*....|....*....|....*
gi 2462617419  65 FVSFDSRSEAEAAKNALNGIRFDPEIPQTLRLEFA 99
Cdd:cd12432    43 YVTYSSEEEAVATREALHGVVWPSSNGKRLKVEFV 77

RNA recognition motif 1 (RRM1) found in the U1A/U2B"/SNF protein family; This subfamily corresponds to the RRM1 of U1A/U2B"/SNF protein family which contains Drosophila sex determination protein SNF and its two mammalian counterparts, U1 small nuclear ribonucleoprotein A (U1 snRNP A or U1-A or U1A) and U2 small nuclear ribonucleoprotein B" (U2 snRNP B" or U2B"), all of which consist of two RNA recognition motifs (RRMs), connected by a variable, flexible linker. SNF is an RNA-binding protein found in the U1 and U2 snRNPs of Drosophila where it is essential in sex determination and possesses a novel dual RNA binding specificity. SNF binds with high affinity to both Drosophila U1 snRNA stem-loop II (SLII) and U2 snRNA stem-loop IV (SLIV). It can also bind to poly(U) RNA tracts flanking the alternatively spliced Sex-lethal (Sxl) exon, as does Drosophila Sex-lethal protein (SXL). U1A is an RNA-binding protein associated with the U1 snRNP, a small RNA-protein complex involved in pre-mRNA splicing. U1A binds with high affinity and specificity to stem-loop II (SLII) of U1 snRNA. It is predominantly a nuclear protein that shuttles between the nucleus and the cytoplasm independently of interactions with U1 snRNA. Moreover, U1A may be involved in RNA 3'-end processing, specifically cleavage, splicing and polyadenylation, through interacting with a large number of non-snRNP proteins. U2B", initially identified to bind to stem-loop IV (SLIV) at the 3' end of U2 snRNA, is a unique protein that comprises of the U2 snRNP. Additional research indicates U2B" binds to U1 snRNA stem-loop II (SLII) as well and shows no preference for SLIV or SLII on the basis of binding affinity. Moreover, U2B" does not require an auxiliary protein for binding to RNA, and its nuclear transport is independent of U2 snRNA binding.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  25 TLFVSGLPLDIKPRE----LYLLFRPFkgyeGSLIK---LTSKQPVG--FVSFDSRSEAEAAKNALNGIRFdpeIPQTLR 95
Cdd:cd12246     1 TLYINNLNEKIKKDElkrsLYALFSQF----GPVLDivaSKSLKMRGqaFVVFKDVESATNALRALQGFPF---YGKPMR 73

                  ....*
gi 2462617419  96 LEFAK 100
Cdd:cd12246    74 IQYAK 78

RNA recognition motif 3 (RRM3) found in yeast negative growth regulatory protein NGR1 (RBP1), yeast protein NAM8 and similar proteins; This subfamily corresponds to the RRM3 of NGR1 and NAM8. NGR1, also termed RNA-binding protein RBP1, is a putative glucose-repressible protein that binds both RNA and single-stranded DNA (ssDNA) in yeast. It may function in regulating cell growth in early log phase, possibly through its participation in RNA metabolism. NGR1 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a glutamine-rich stretch that may be involved in transcriptional activity. In addition, NGR1 has an asparagine-rich region near the carboxyl terminus which also harbors a methionine-rich region. The family also includes protein NAM8, which is a putative RNA-binding protein that acts as a suppressor of mitochondrial splicing deficiencies when overexpressed in yeast. It may be a non-essential component of the mitochondrial splicing machinery. Like NGR1, NAM8 contains two RRMs.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2462617419  25 TLFVSGLPLDIKPRELYLLFRPFkgyeGSL--IKLTSKQPVGFVSFDSRSEAEAAKNALNG 83
Cdd:cd12346     3 TVFVGGLDPNVTEEDLRVLFGPF----GEIvyVKIPPGKGCGFVQFVNRASAEAAIQKLQG 59

RNA recognition motif 1 (RRM1) found in fission yeast pre-mRNA-splicing factor Srp1p and similar proteins; This subgroup corresponds to the RRM domain in Srp1p encoded by gene srp1 from fission yeast Schizosaccharomyces pombe. It plays a role in the pre-mRNA splicing process, but not essential for growth. Srp1p is closely related to the SR protein family found in metazoa. It contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a glycine hinge and a RS domain in the middle, and a C-terminal domain. Some family members also contain another RRM domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  25 TLFVSGLPLDIKPRELYLLFRPFkgyeGSLIKL-------TSKQPVGFVSFDSRSEAEAAKNALNGIRFdPEIPQTLRLE 97
Cdd:cd12467     1 TLYVTGFGAETRARDLAYEFERY----GRLVRCdippprtFQSRPFAFVEYESHRDAEDAYEEMHGRRF-PDTGDTLHVQ 75

                  ...
gi 2462617419  98 FAK 100
Cdd:cd12467    76 WAK 78

RNA recognition motif 2 (RRM2) found in vertebrate Hu-antigen D (HuD); This subgroup corresponds to the RRM2 of HuD, also termed ELAV-like protein 4 (ELAV-4), or paraneoplastic encephalomyelitis antigen HuD, one of the neuronal members of the Hu family. The neuronal Hu proteins play important roles in neuronal differentiation, plasticity and memory. HuD has been implicated in various aspects of neuronal function, such as the commitment and differentiation of neuronal precursors as well as synaptic remodeling in mature neurons. HuD also functions as an important regulator of mRNA expression in neurons by interacting with AU-rich RNA element (ARE) and stabilizing multiple transcripts. Moreover, HuD regulates the nuclear processing/stability of N-myc pre-mRNA in neuroblastoma cells and also regulates the neurite elongation and morphological differentiation. HuD specifically binds poly(A) RNA. Like other Hu proteins, HuD contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an ARE. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFKGYEGSLIKLTS----KQPVGFVSFDSRSEAEAAKNALNG 83
Cdd:cd12774     8 LYVSGLPKTMTQKELEQLFSQYGRIITSRILVDQvtgvSRGVGFIRFDKRIEAEEAIKGLNG 69

RNA recognition motif 2 (RRM2) found in Drosophila melanogaster sex determination protein SNF and similar proteins; This subgroup corresponds to the RRM2 of SNF (Sans fille), also termed U1 small nuclear ribonucleoprotein A (U1 snRNP A or U1-A or U1A), an RNA-binding protein found in the U1 and U2 snRNPs of Drosophila. It is essential in Drosophila sex determination and possesses a novel dual RNA binding specificity. SNF binds with high affinity to both Drosophila U1 snRNA stem-loop II (SLII) and U2 snRNA stem-loop IV (SLIV). It can also bind to poly(U) RNA tracts flanking the alternatively spliced Sex-lethal (Sxl) exon, as does Drosophila Sex-lethal protein (SXL). SNF contains two RNA recognition motifs (RRMs); it can self-associate through RRM1, and each RRM can recognize poly(U) RNA binding independently.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 2462617419  24 RTLFVSGLPLDIKPRELYLLFRPFKGYEGSLIkLTSKQPVGFVSFDSRSEAEAAKNALNGIRFDPEipQTLRLEFAK 100
Cdd:cd12479     6 QILFLTNLPEETNEMMLSMLFNQFPGFKEVRL-VPGRHDIAFVEFENEVQSAAAKEALQGFKITPT--HAMKITFAK 79

RNA recognition motif 2 (RRM2) found in the c-myc gene single-strand binding proteins (MSSP) family; This subfamily corresponds to the RRM2 of c-myc gene single-strand binding proteins (MSSP) family, including single-stranded DNA-binding protein MSSP-1 (also termed RBMS1 or SCR2) and MSSP-2 (also termed RBMS2 or SCR3). All MSSP family members contain two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), both of which are responsible for the specific DNA binding activity. Both, MSSP-1 and -2, have been identified as protein factors binding to a putative DNA replication origin/transcriptional enhancer sequence present upstream from the human c-myc gene in both single- and double-stranded forms. Thus they have been implied in regulating DNA replication, transcription, apoptosis induction, and cell-cycle movement, via the interaction with C-MYC, the product of protooncogene c-myc. Moreover, they family includes a new member termed RNA-binding motif, single-stranded-interacting protein 3 (RBMS3), which is not a transcriptional regulator. RBMS3 binds with high affinity to A/U-rich stretches of RNA, and to A/T-rich DNA sequences, and functions as a regulator of cytoplasmic activity. In addition, a putative meiosis-specific RNA-binding protein termed sporulation-specific protein 5 (SPO5, or meiotic RNA-binding protein 1, or meiotically up-regulated gene 12 protein), encoded by Schizosaccharomyces pombe Spo5/Mug12 gene, is also included in this family. SPO5 is a novel meiosis I regulator that may function in the vicinity of the Mei2 dot.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFkgyeGSLI--------KLTSKQpVGFVSFDSRSEAEAAKNALNGIRFDPEIPQT--LR 95
Cdd:cd12244     3 LYISNLPLDMDEQDLENMLKPF----GQVIstrilrdsKGQSRG-VGFARMESREKCEDVISKFNGKVLKTPSASGepLL 77

                  ....
gi 2462617419  96 LEFA 99
Cdd:cd12244    78 VKFA 81

RNA recognition motif 1 (RRM1) found in serine/arginine-rich splicing factor 1 (SRSF1) and similar proteins; This subgroup corresponds to the RRM1 in three serine/arginine (SR) proteins: serine/arginine-rich splicing factor 1 (SRSF1 or ASF-1), serine/arginine-rich splicing factor 9 (SRSF9 or SRp30C), and plant pre-mRNA-splicing factor SF2 (SR1). SRSF1 is a shuttling SR protein involved in constitutive and alternative splicing, nonsense-mediated mRNA decay (NMD), mRNA export and translation. It also functions as a splicing-factor oncoprotein that regulates apoptosis and proliferation to promote mammary epithelial cell transformation. SRSF9 has been implicated in the activity of many elements that control splice site selection, the alternative splicing of the glucocorticoid receptor beta in neutrophils and in the gonadotropin-releasing hormone pre-mRNA. It can also interact with other proteins implicated in alternative splicing, including YB-1, rSLM-1, rSLM-2, E4-ORF4, Nop30, and p32. Both, SRSF1 and SRSF9, contain two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal RS domains rich in serine-arginine dipeptides. In contrast, SF2 contains two N-terminal RRMs and a C-terminal PSK domain rich in proline, serine and lysine residues.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2462617419  25 TLFVSGLPLDIKPRELYLLFRPFkgyeGSLIKLTSKQPVG-----FVSFDSRSEAEAAKNALNGIRFDpeiPQTLRLEF 98
Cdd:cd12338     1 RIYVGNLPGDIRERDIEDLFYKY----GPILAIDLKNRRRgppfaFVEFEDPRDAEDAIRGRDGYDFD---GYRLRVEF 72

RNA recognition motif 4 (RRM4) found in yeast multiple RNA-binding domain-containing protein 1 (MRD1) and similar proteins; This subfamily corresponds to the RRM4 of MRD1which is encoded by a novel yeast gene MRD1 (multiple RNA-binding domain). It is well-conserved in yeast and its homologs exist in all eukaryotes. MRD1 is present in the nucleolus and the nucleoplasm. It interacts with the 35 S precursor rRNA (pre-rRNA) and U3 small nucleolar RNAs (snoRNAs). MRD1 is essential for the initial processing at the A0-A2 cleavage sites in the 35 S pre-rRNA. It contains 5 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which may play an important structural role in organizing specific rRNA processing events.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2462617419  25 TLFVSGLPLDIKPRELYLLFRPFKGYEGSLIKLTS--KQP-------VGFVSFDSRSEAEAAKNALNGIRFD 87
Cdd:cd12319     2 TLFVKNLNFSTTNQHLTDVFKHLDGFVFARVKTKPdpKRPgktlsmgFGFVGFKTKEQAQAALKAMDGFVLD 73

RNA recognition motif 2 (RRM2) found in vertebrate Hu-antigen R (HuR); This subgroup corresponds to the RRM2 of HuR, also termed ELAV-like protein 1 (ELAV-1), the ubiquitously expressed Hu family member. It has a variety of biological functions mostly related to the regulation of cellular response to DNA damage and other types of stress. HuR has an anti-apoptotic function during early cell stress response. It binds to mRNAs and enhances the expression of several anti-apoptotic proteins, such as p21waf1, p53, and prothymosin alpha. HuR also has pro-apoptotic function by promoting apoptosis when cell death is unavoidable. Furthermore, HuR may be important in muscle differentiation, adipogenesis, suppression of inflammatory response and modulation of gene expression in response to chronic ethanol exposure and amino acid starvation. Like other Hu proteins, HuR contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE). RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFKGYEGS--LIKLTS--KQPVGFVSFDSRSEAEAAKNALNG 83
Cdd:cd12773     3 LYISGLPRTMTQKDVEDMFSRFGRIINSrvLVDQATglSRGVAFIRFDKRSEAEEAITNFNG 64

RNA recognition motif 2 (RRM2) found in CUGBP Elav-like family member CELF-3, CELF-4, CELF-5, CELF-6 and similar proteins; This subgroup corresponds to the RRM2 of CELF-3, CELF-4, CELF-5, and CELF-6, all of which belong to the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) family of RNA-binding proteins that display dual nuclear and cytoplasmic localizations and have been implicated in the regulation of pre-mRNA splicing and in the control of mRNA translation and deadenylation. CELF-3, expressed in brain and testis only, is also known as bruno-like protein 1 (BRUNOL-1), or CAG repeat protein 4, or CUG-BP- and ETR-3-like factor 3, or embryonic lethal abnormal vision (ELAV)-type RNA-binding protein 1 (ETR-1), or expanded repeat domain protein CAG/CTG 4, or trinucleotide repeat-containing gene 4 protein (TNRC4). It plays an important role in the pathogenesis of tauopathies. CELF-3 contains three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein. The effect of CELF-3 on tau splicing is mediated mainly by the RNA-binding activity of RRM2. The divergent linker region might mediate the interaction of CELF-3 with other proteins regulating its activity or involved in target recognition. CELF-4, being highly expressed throughout the brain and in glandular tissues, moderately expressed in heart, skeletal muscle, and liver, is also known as bruno-like protein 4 (BRUNOL-4), or CUG-BP- and ETR-3-like factor 4. Like CELF-3, CELF-4 also contain three highly conserved RRMs. The splicing activation or repression activity of CELF-4 on some specific substrates is mediated by its RRM1/RRM2. On the other hand, both RRM1 and RRM2 of CELF-4 can activate cardiac troponin T (cTNT) exon 5 inclusion. CELF-5, expressed in brain, is also known as bruno-like protein 5 (BRUNOL-5), or CUG-BP- and ETR-3-like factor 5. Although its biological role remains unclear, CELF-5 shares same domain architecture with CELF-3. CELF-6, being strongly expressed in kidney, brain, and testis, is also known as bruno-like protein 6 (BRUNOL-6), or CUG-BP- and ETR-3-like factor 6. It activates exon inclusion of a cardiac troponin T minigene in transient transfection assays in a muscle-specific splicing enhancer (MSE)-dependent manner and can activate inclusion via multiple copies of a single element, MSE2. CELF-6 also promotes skipping of exon 11 of insulin receptor, a known target of CELF activity that is expressed in kidney. In addition to three highly conserved RRMs, CELF-6 also possesses numerous potential phosphorylation sites, a potential nuclear localization signal (NLS) at the C terminus, and an alanine-rich region within the divergent linker region.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  24 RTLFVSGLPLDIKPRELYLLFRPFkgyeGSLIKLT-------SKQPVGFVSFDSRSEAEAAKNALNGIRFDPEIPQTLRL 96
Cdd:cd12635     2 RKLFVGMLGKQQSEDDVRRLFEPF----GSIEECTilrgpdgNSKGCAFVKFSSHAEAQAAINALHGSQTMPGASSSLVV 77

                  ...
gi 2462617419  97 EFA 99
Cdd:cd12635    78 KFA 80

hnRNP-L/PTB/hephaestus splicing factor family; Included in this family of heterogeneous ribonucleoproteins are PTB (polypyrimidine tract binding protein) and hnRNP-L. These proteins contain four RNA recognition motifs (rrm: pfam00067).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  40 LYLLFRPFkgyeGSLIKL-TSKQPVGF---VSFDSRSEAEAAKNALNGirfdPEIPQ---TLRLEFAKA---NTKMAKNK 109
Cdd:TIGR01649 113 LYQIFNPY----GKVLRIvTFTKNNVFqalVEFESVNSAQHAKAALNG----ADIYNgccTLKIEYAKPtrlNVKYNDDD 184

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419 110 LVGTPNPSTP-------LPN---TVPQFIAREPYELTVPAlYPSSPEVWAPYPL----YPAELAPALPPPAFTYPAsLHA 175
Cdd:TIGR01649 185 SRDYTNPDLPgrrdpglDQThrqRQPALLGQHPSSYGHDG-YSSHGGPLAPLAGgdrmGPPHGPPSRYRPAYEAAP-LAP 262

                         170       180       190
                  ....*....|....*....|....*....|.
gi 2462617419 176 QVSSPPPAMGALCPRPVLSHLSQEGSSNSAL 206
Cdd:TIGR01649 263 AISSYGPAGGGPGSVLMVSGLHQEKVNCDRL 293

RNA recognition motif 2 (RRM2) found in Drosophila sex-lethal (SXL) and similar proteins; This subfamily corresponds to the RRM2 of the sex-lethal protein (SXL) which governs sexual differentiation and X chromosome dosage compensation in Drosophila melanogaster. It induces female-specific alternative splicing of the transformer (tra) pre-mRNA by binding to the tra uridine-rich polypyrimidine tract at the non-sex-specific 3' splice site during the sex-determination process. SXL binds also to its own pre-mRNA and promotes female-specific alternative splicing. SXL contains an N-terminal Gly/Asn-rich domain that may be responsible for the protein-protein interaction, and tandem RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), that show high preference to bind single-stranded, uridine-rich target RNA transcripts.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2462617419  26 LFVSGLPLDIKPRELYLLFrpfkGYEGSLI-------KLTSK-QPVGFVSFDSRSEAEAAKNALNGIRF 86
Cdd:cd12651     5 LYVTNLPRTITEDELDTIF----GAYGNIVqknllrdKLTGRpRGVAFVRYDKREEAQAAISALNGTIP 69

RNA recognition motif (RRM) found in heterogeneous nuclear ribonucleoprotein G (hnRNP G), Y chromosome RNA recognition motif 1 (hRBMY), testis-specific heterogeneous nuclear ribonucleoprotein G-T (hnRNP G-T) and similar proteins; This subfamily corresponds to the RRM domain of hnRNP G, also termed glycoprotein p43 or RBMX, an RNA-binding motif protein located on the X chromosome. It is expressed ubiquitously and has been implicated in the splicing control of several pre-mRNAs. Moreover, hnRNP G may function as a regulator of transcription for SREBP-1c and GnRH1. Research has shown that hnRNP G may also act as a tumor-suppressor since it upregulates the Txnip gene and promotes the fidelity of DNA end-joining activity. In addition, hnRNP G appears to play a critical role in proper neural development of zebrafish and frog embryos. The family also includes several paralogs of hnRNP G, such as hRBMY and hnRNP G-T (also termed RNA-binding motif protein, X-linked-like-2). Both, hRBMY and hnRNP G-T, are exclusively expressed in testis and critical for male fertility. Like hnRNP G, hRBMY and hnRNP G-T interact with factors implicated in the regulation of pre-mRNA splicing, such as hTra2-beta1 and T-STAR. Although members in this family share a high conserved N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), they appear to recognize different RNA targets. For instance, hRBMY interacts specifically with a stem-loop structure in which the loop is formed by the sequence CA/UCAA. In contrast, hnRNP G associates with single stranded RNA sequences containing a CCA/C motif. In addition to the RRM, hnRNP G contains a nascent transcripts targeting domain (NTD) in the middle region and a novel auxiliary RNA-binding domain (RBD) in its C-terminal region. The C-terminal RBD exhibits distinct RNA binding specificity, and would play a critical role in the regulation of alternative splicing by hnRNP G.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPF-KGYEGSLIK--LTSK-QPVGFVSFDSRSEAEAAKNALNGIRFD 87
Cdd:cd12382     4 LFIGGLNTETNEKALEAVFGKYgRIVEVLLMKdrETNKsRGFAFVTFESPADAKDAARDMNGKELD 69

RNA recognition motif 2 (RRM2) found in vertebrate U1 small nuclear ribonucleoprotein A (U1 snRNP A or U1-A or U1A); This subgroup corresponds to the RRM2 of U1A (also termed U1 snRNP A or U1-A), an RNA-binding protein associated with the U1 snRNP, a small RNA-protein complex involved in pre-mRNA splicing. U1A binds with high affinity and specificity to stem-loop II (SLII) of U1 snRNA. It is predominantly a nuclear protein that shuttles between the nucleus and the cytoplasm independently of interactions with U1 snRNA. U1A may be involved in RNA 3'-end processing, specifically cleavage, splicing and polyadenylation, through interacting with a large number of non-snRNP proteins, including polypyrimidine tract binding protein (PTB), polypyrimidine-tract binding protein-associated factor (PSF), and non-POU-domain-containing, octamer-binding (NONO), DEAD (Asp-Glu-Ala-Asp) box polypeptide 5 (DDX5). U1A also binds to a flavivirus NS5 protein and plays an important role in virus replication. It contains two RNA recognition motifs (RRMs); the N-terminal RRM (RRM1) binds tightly and specifically to the U1 snRNA SLII and its own 3'-UTR, while in contrast, the C-terminal RRM (RRM2) does not appear to associate with any RNA and it may be free for binding other proteins. U1A also contains a proline-rich region, and a nuclear localization signal (NLS) in the central domain that is responsible for its nuclear import.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFKGYEGSLIkLTSKQPVGFVSFDSRSEAEAAKNALNGIRFDPEipQTLRLEFAK 100
Cdd:cd12480    14 LFLTNLPEETNELMLSMLFNQFPGFKEVRL-VPGRHDIAFVEFDNEVQAGAAREALQGFKITQS--NAMKISFAK 85

RNA recognition motif 1 (RRM1) found in vertebrate polypyrimidine tract-binding protein (PTB)-associated-splicing factor (PSF); This subgroup corresponds to the RRM1 of PSF, also termed proline- and glutamine-rich splicing factor, or 100 kDa DNA-pairing protein (POMp100), or 100 kDa subunit of DNA-binding p52/p100 complex, a multifunctional protein that mediates diverse activities in the cell. It is ubiquitously expressed and highly conserved in vertebrates. PSF binds not only RNA but also both single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) and facilitates the renaturation of complementary ssDNAs. Besides, it promotes the formation of D-loops in superhelical duplex DNA, and is involved in cell proliferation. PSF can also interact with multiple factors. It is an RNA-binding component of spliceosomes and binds to insulin-like growth factor response element (IGFRE). PSF functions as a transcriptional repressor interacting with Sin3A and mediating silencing through the recruitment of histone deacetylases (HDACs) to the DNA binding domain (DBD) of nuclear hormone receptors. Additionally, PSF is an essential pre-mRNA splicing factor and is dissociated from PTB and binds to U1-70K and serine-arginine (SR) proteins during apoptosis. PSF forms a heterodimer with the nuclear protein p54nrb, also known as non-POU domain-containing octamer-binding protein (NonO). The PSF/p54nrb complex displays a variety of functions, such as DNA recombination and RNA synthesis, processing, and transport. PSF contains two conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which are responsible for interactions with RNA and for the localization of the protein in speckles. It also contains an N-terminal region rich in proline, glycine, and glutamine residues, which may play a role in interactions recruiting other molecules.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFKgyEGSLIKLTSKQPVGFVSFDSRSEAEAAKNALNGIrfdPEIPQTLRLEF 98
Cdd:cd12587     4 LFVGNLPADITEDEFKRLFAKYG--EPGEVFINKGKGFGFIKLESRALAEIAKAELDDT---PMRGRQLRVRF 71

RNA recognition motif 2 (RRM2) found in CUGBP Elav-like family member CELF-3, CELF-4, CELF-5, CELF-6 and similar proteins; This subgroup corresponds to the RRM3 of CELF-3, CELF-4, CELF-5, and CELF-6, all of which belong to the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) family of RNA-binding proteins that display dual nuclear and cytoplasmic localizations and have been implicated in the regulation of pre-mRNA splicing and in the control of mRNA translation and deadenylation. CELF-3, expressed in brain and testis only, is also known as bruno-like protein 1 (BRUNOL-1), or CAG repeat protein 4, or CUG-BP- and ETR-3-like factor 3, or embryonic lethal abnormal vision (ELAV)-type RNA-binding protein 1 (ETR-1), or expanded repeat domain protein CAG/CTG 4, or trinucleotide repeat-containing gene 4 protein (TNRC4). It plays an important role in the pathogenesis of tauopathies. CELF-3 contains three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein.The effect of CELF-3 on tau splicing is mediated mainly by the RNA-binding activity of RRM2. The divergent linker region might mediate the interaction of CELF-3 with other proteins regulating its activity or involved in target recognition. CELF-4, highly expressed throughout the brain and in glandular tissues, moderately expressed in heart, skeletal muscle, and liver, is also known as bruno-like protein 4 (BRUNOL-4), or CUG-BP- and ETR-3-like factor 4. Like CELF-3, CELF-4 also contains three highly conserved RRMs. The splicing activation or repression activity of CELF-4 on some specific substrates is mediated by its RRM1/RRM2. Both, RRM1 and RRM2 of CELF-4, can activate cardiac troponin T (cTNT) exon 5 inclusion. CELF-5, expressed in brain, is also known as bruno-like protein 5 (BRUNOL-5), or CUG-BP- and ETR-3-like factor 5. Although its biological role remains unclear, CELF-5 shares same domain architecture with CELF-3. CELF-6, strongly expressed in kidney, brain, and testis, is also known as bruno-like protein 6 (BRUNOL-6), or CUG-BP- and ETR-3-like factor 6. It activates exon inclusion of a cardiac troponin T minigene in transient transfection assays in an muscle-specific splicing enhancer (MSE)-dependent manner and can activate inclusion via multiple copies of a single element, MSE2. CELF-6 also promotes skipping of exon 11 of insulin receptor, a known target of CELF activity that is expressed in kidney. In addition to three highly conserved RRMs, CELF-6 also possesses numerous potential phosphorylation sites, a potential nuclear localization signal (NLS) at the C terminus, and an alanine-rich region within the divergent linker region.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2462617419  26 LFVSGLPLDIKPRELYLLFRPFkgyeGSLI-------KLTSKQPV-GFVSFDSRSEAEAAKNALNGIR 85
Cdd:cd12639     7 LFIYHLPQEFGDAELMQMFLPF----GNVIsakvfvdRATNQSKCfGFVSFDNPASAQAAIQAMNGFQ 70

RNA recognition motif (RRM) found in alkylated DNA repair protein alkB homolog 8 (ALKBH8) and similar proteins; This subfamily corresponds to the RRM of ALKBH8, also termed alpha-ketoglutarate-dependent dioxygenase ABH8, or S-adenosyl-L-methionine-dependent tRNA methyltransferase ABH8, expressed in various types of human cancers. It is essential in urothelial carcinoma cell survival mediated by NOX-1-dependent ROS signals. ALKBH8 has also been identified as a tRNA methyltransferase that catalyzes methylation of tRNA to yield 5-methylcarboxymethyl uridine (mcm5U) at the wobble position of the anticodon loop. Thus, ALKBH8 plays a crucial role in the DNA damage survival pathway through a distinct mechanism involving the regulation of tRNA modification. ALKBH8 localizes to the cytoplasm. It contains the characteristic AlkB domain that is composed of a tRNA methyltransferase motif, a motif homologous to the bacterial AlkB DNA/RNA repair enzyme, and a dioxygenase catalytic core domain encompassing cofactor-binding sites for iron and 2-oxoglutarate. In addition, unlike other AlkB homologs, ALKBH8 contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal S-adenosylmethionine (SAM)-dependent methyltransferase (MT) domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462617419  24 RTLFVS--GLPLDIKPRELYLLFRPFKGYEgSLIKLTSKqPVGFVSFDSRSEAEAAKNALNGIR-FDPEIPQTLRLEFAK 100
Cdd:cd12431     2 QHLVVAngGLGNGVSREQLLEVFEKYGTVE-DIVMLPGK-PYSFVSFKSVEEAAKAYNALNGKElELPQQNVPLYLSFVE 79

                  .
gi 2462617419 101 A 101
Cdd:cd12431    80 K 80

RNA recognition motif (RRM) found in transformer-2 protein homolog TRA2-alpha, TRA2-beta and similar proteins; This subfamily corresponds to the RRM of two mammalian homologs of Drosophila transformer-2 (Tra2), TRA2-alpha, TRA2-beta (also termed SFRS10), and similar proteins found in eukaryotes. TRA2-alpha is a 40-kDa serine/arginine-rich (SR) protein that specifically binds to gonadotropin-releasing hormone (GnRH) exonic splicing enhancer on exon 4 (ESE4) and is necessary for enhanced GnRH pre-mRNA splicing. It strongly stimulates GnRH intron A excision in a dose-dependent manner. In addition, TRA2-alpha can interact with either 9G8 or SRp30c, which may also be crucial for ESE-dependent GnRH pre-mRNA splicing. TRA2-beta is a serine/arginine-rich (SR) protein that controls the pre-mRNA alternative splicing of the calcitonin/calcitonin gene-related peptide (CGRP), the survival motor neuron 1 (SMN1) protein and the tau protein. Both, TRA2-alpha and TRA2-beta, contains a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), flanked by the N- and C-terminal arginine/serine (RS)-rich regions.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2462617419  23 VRTLFVSGLPLDIKPRELYLLFRPFkgyeGSLIKLtskQPV-----------GFVSFDSRSEAEAAKNALNGIRFD 87
Cdd:cd12363     1 SRCLGVFGLSLYTTERDLREVFSRY----GPIEKV---QVVydqqtgrsrgfGFVYFESVEDAKEAKERLNGQEID 69