Alternative titles; symbols
HGNC Approved Gene Symbol: SNRNP200
Cytogenetic location: 2q11.2 Genomic coordinates (GRCh38): 2:96,274,338-96,305,546 (from NCBI)
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 2q11.2 | Retinitis pigmentosa 33 | 610359 | Autosomal dominant | 3 |
Many of the factors involved in the splicing of RNA molecules are conserved in eukaryotes, including the small nuclear ribonuclear particles (snRNPs) U1, U2, U4/U6 and U5, and a number of non-snRNP splicing factors. The snRNPs contain both RNA and protein. During the presplicing reaction, U1 and U2 snRNA are involved in distinguishing intron from exon sequence. U4/U6 and U5 act as a tri-snRNP complex (U4/U6.U5) to align RNA during splice reactions. The RNA to be spliced undergoes several conformational changes during spliceosome assembly and the splicing reactions. A group of non-snRNP splicing factors have been identified in yeast and may be involved in the dynamic changes associated with splicing. These proteins fall into 2 classes; Prp5 and Prp28 belong to the DEAD-box of putative ATP-dependent RNA helicases, and Prp2, Prp16, and Prp22 belong to a family of putative RNA helicases containing a DEAH box. DEAD and DEAH refer to a sequence motif present in these proteins (asp-glu-ala-asp or asp-glu-ala-his) (summary by Lauber et al., 1996).
By searching for sequences with the potential to encode large proteins expressed in brain, Nagase et al. (1998) identified a partial cDNA encoding SNRNP200, which they called KIAA0788. Sequence analysis predicted that the 1,324-amino acid protein is 46% identical to a putative RNA helicase. RT-PCR analysis followed by ELISA detected high-level, ubiquitous expression of KIAA0788.
Lauber et al. (1996) described the molecular cloning of a U5-specific 200-kD (U5-200kD) protein and demonstrated that it belongs to the DEXH-box family of putative RNA helicases. The protein was initially described as human but was later found to be based on a mouse sequence that is homologous to KIAA0788. This protein contains 2 DEXH motifs (DEIH and DEVH), making it the first such protein to be identified. Lauber et al. (1996) searched the yeast genome database and identified a homologous protein, Snu246, a 246-kD protein which they showed to be essential in yeast and required for pre-mRNA splicing in vivo. Lauber et al. (1996) showed that anti-U5-200kD antibodies specifically block the second step (lariat excision) of mammalian splicing in vitro.
Zhao et al. (2009) stated that SNRNP200 encodes a 2,136-amino acid protein composed of 2 DEXH/D box ATPase domains, each followed by a Sec63 domain. Noting that SNRNP200 expression was previously detected in a retina-derived cDNA library (NbLIb0013), Zhao et al. (2009) analyzed SNRNP200 expression in other human tissues and demonstrated expression in heart, brain, placenta, lung, liver, skeletal muscle, kidney, and pancreas.
Zhao et al. (2009) stated that the SNRNP200 gene contains 45 exons.
Zhao et al. (2009) stated that the SNRNP200 gene maps to chromosome 2q11.2.
Crystal Structure
Mozaffari-Jovin et al. (2013) showed by crystal structure and biochemical analyses that the Prp8 (607300) protein, a major regulator of the spliceosome, can insert its C-terminal tail into the RNA-binding tunnel of Brr2, thereby intermittently blocking Brr2's RNA-binding, adenosine triphosphatase, and U4/U6-unwinding activities. Inefficient Brr2 repression is the only recognizable phenotype associated with certain retinitis pigmentosa-linked Prp8 mutations that map to its C-terminal tail. Mozaffari-Jovin et al. (2013) concluded that their data showed how a Ski2-like RNA helicase can be reversibly inhibited by a protein cofactor that directly competes with RNA substrate binding.
Cryoelectron Microscopy
Using cryoelectron microscopy single-particle reconstruction of the S. cerevisiae tri-snRNP at 5.9-angstrom resolution, Nguyen et al. (2015) determined the complete organization of the tri-snRNP RNA and protein components, including Brr2, Snu114 (EFTUD2; 603892), and Prp8. The single-stranded region of U4 snRNA (see 620822) between its 3-prime stem-loop and the U4/U6 (see 180692) snRNA stem I was loaded into the Brr2 helicase active site ready for unwinding. Snu114 and the N-terminal domain of Prp8 positioned U5 snRNA (see 180691) to insert its loop I, which aligns exons for splicing, into the Prp8 active-site cavity.
Charenton et al. (2019) reported cryoelectron microscopy structures of the human pre-B spliceosome complex captured before U1 snRNP (see 180740) dissociation at 3.3-angstrom core resolution and the human U4/U6.U5 tri-snRNP at 2.9-angstrom resolution. U1 snRNP inserts the 5-prime splice site-U1 snRNA helix between the 2 RecA domains of the Prp28 DEAD-box helicase (DDX23; 612172). ATP-dependent closure of the Prp28 RecA domains releases the 5-prime splice site to pair with the nearby U6 ACAGAGA-box sequence presented as a mobile loop. The structures suggested that formation of the 5-prime splice site-ACAGAGA helix triggers remodeling of an intricate protein-RNA network to induce Brr2 helicase relocation to its loading sequence in U4 snRNA, enabling Brr2 to unwind the U4/U6 snRNA duplex to allow U6 snRNA to form the catalytic center of the spliceosome.
Cvackova et al. (2014) found that knockdown of BBR2 via small interfering RNA in HeLa cells reduced the splicing efficiency of reporter minigenes, but in a manner that depended upon the genes on which the reporters were based. Knockdown of BBR2 tended to increase use of cryptic 5-prime splice sites and reduce the use of conventional splice sites. Cvackova et al. (2014) concluded that BBR2 is a factor in 5-prime splice site recognition.
In a 4-generation Chinese family with autosomal dominant retinitis pigmentosa (adRP) mapping to chromosome 2cen-q12.1, previously studied by Zhao et al. (2006), Zhao et al. (2009) analyzed the candidate gene SNRNP200 and identified a heterozygous missense mutation (S1087L; 601664.0001) that segregated fully with the disease. In vitro studies suggested that the mutation impairs ATP-dependent unwinding of U4/U6.
In a 4-generation Chinese family with adRP mapping to chromosome 2q11, Li et al. (2010) sequenced the SNRNP200 (ASCC3L1) gene and identified a heterozygous missense mutation (R1090L; 601664.0002) that segregated with the disease.
In affected members of a 4-generation Chinese family segregating adRP, Liu et al. (2012) identified heterozygosity for a missense mutation in the SNRNP200 gene (Q885E; 601664.0003).
In a study of 1,751 knockout alleles created by the International Mouse Phenotyping Consortium (IMPC), Dickinson et al. (2016) found that knockout of the mouse homolog of human SNRNP200 is homozygous-lethal (defined as absence of homozygous mice after screening of at least 28 pups before weaning).
Kukhtar et al. (2020) generated C. elegans homozygous for mutations in Prpf8 or Snrnp200 that mimicked mutations in humans associated with adRP. All mutant animals displayed variable temperature-sensitive developmental defects and reduced fertility, and the authors divided the mutations into 2 types: mutations corresponding to val683 to leu (V683L) in human SNRNP200 and a deletion of his2309 (H2309del) in human PRPF8 were strong temperature-sensitive alleles, whereas mutations corresponding to arg2310 to gly (R2310G) in human PRPF8 and ser1087 to leu (S1087L) in human SNRNP200 were weak alleles. RNA interference screens identified splicing factors as potential modifiers of the mutation corresponding to R2310G in human PRPF8. A drug screen of the mutation corresponding to H2309del in human PRPF8 did not reveal molecules capable of alleviating temperature-sensitive sterility, but it showed that dequalinium chloride exacerbated the phenotype.
In 12 affected members of a 4-generation Chinese family with autosomal dominant retinitis pigmentosa mapping to chromosome 2cen-q12.1 (RP33; 610359), previously studied by Zhao et al. (2006), Zhao et al. (2009) identified a 3260C-T transition in exon 25 of the SNRNP200 gene, resulting in a ser1087-to-leu (S1087L) substitution at a highly conserved residue within the 'ratchet' helix of the first Sec63 domain. The mutation was not found in 13 unaffected family members or in 400 unaffected controls. Assays in budding yeast revealed that a mutation corresponding to S1087L markedly impaired ATP-dependent unwinding of U4/U6 small nuclear RNAs.
Cvackova et al. (2014) found that the S1087L substitution had no effect on targeting of BBR2 to nuclear speckles or incorporation of BRR2 into snRNPs. However, the mutation reduced the time with which BRR2 interacted with pre-mRNAs during splicing and increased the use of cryptic splice sites in a reporter based on the beta-globin gene (HBB; 141900). Splicing of other reporter genes was not affected, suggesting gene-specific effects of the mutation on 5-prime splice site selection.
In 12 affected members of a 4-generation Chinese family segregating autosomal dominant retinitis pigmentosa (RP33; 610359), Li et al. (2010) identified heterozygosity for a 3269G-T transversion in exon 25 of the SNRNP200 gene, resulting in an arg1090-to-leu (R1090L) substitution at a conserved residue in the first Sec63 motif. The mutation was not found in unaffected family members or in 100 ethnically matched controls.
Cvackova et al. (2014) found that the R1090L substitution had no effect on targeting of BBR2 to nuclear speckles or incorporation of BRR2 into snRNPs. However, the mutation reduced the time with which BRR2 interacted with pre-mRNAs during splicing and increased the use of cryptic splice sites in a reporter based on the beta-globin gene (HBB; 141900). Splicing of other reporter genes was not affected, suggesting gene-specific effects of the mutation on 5-prime splice site selection.
In affected members of a 4-generation Chinese family with retinitis pigmentosa (RP33; 610359), Liu et al. (2012) identified heterozygosity for a 2653C-G transversion in exon 20 of the SNRNP200 gene, resulting in a gln885-to-glu (Q885E) substitution at a highly conserved residue in the region containing the first DExD-helicase domain. The mutation was not found in unaffected family members or in 100 controls.
Charenton, C., Wilkinson, M. E., Nagai, K. Mechanism of 5-prime splice site transfer for human spliceosome activation. Science 364: 362-367, 2019. [PubMed: 30975767] [Full Text: https://doi.org/10.1126/science.aax3289]
Cvackova, Z., Mateju, D., Stanek, D. Retinitis pigmentosa mutations of SNRNP200 enhance cryptic splice-site recognition. Hum. Mutat. 35: 308-317, 2014. [PubMed: 24302620] [Full Text: https://doi.org/10.1002/humu.22481]
Dickinson, M. E., Flenniken, A. M., Ji, X., Teboul, L., Wong, M. D., White, J. K., Meehan, T. F., Weninger, W. J., Westerberg, H., Adissu, H., Baker, C. N., Bower, L., and 73 others. High-throughput discovery of novel developmental phenotypes. Nature 537: 508-514, 2016. Note: Erratum: Nature 551: 398 only, 2017. [PubMed: 27626380] [Full Text: https://doi.org/10.1038/nature19356]
Kukhtar, D., Rubio-Pena, K., Serrat, X., Ceron, J. Mimicking of splicing-related retinitis pigmentosa mutations in C. elegans allow drug screens and identification of disease modifiers. Hum. Molec. Genet. 29: 756-765, 2020. [PubMed: 31919495] [Full Text: https://doi.org/10.1093/hmg/ddz315]
Lauber, J., Fabrizio, P., Teigelkamp, S., Lane, W. S., Hartmann, E., Luhrmann, R. The HeLa 200 kDa U5 snRNP-specific protein and its homologue in Saccharomyces cerevisiae are members of the DEXH-box protein family of putative RNA helicases. EMBO J. 15: 4001-4015, 1996. [PubMed: 8670905]
Li, N., Mei, H., MacDonald, I. M., Jiao, X., Hejtmancik, J. F. Mutations in ASCC3L1 on 2q11.2 are associated with autosomal dominant retinitis pigmentosa in a Chinese family. Invest. Ophthal. Vis. Sci. 51: 1036-1043, 2010. [PubMed: 19710410] [Full Text: https://doi.org/10.1167/iovs.09-3725]
Liu, T., Jin, X., Zhang, X., Yuan, H., Cheng, J., Lee, J., Zhang, B., Zhang, M., Wu, J., Wang, L., Tian, G., Wang, W. A novel missense SNRNP200 mutation associated with autosomal dominant retinitis pigmentosa in a Chinese family. PLoS One 7: e45464, 2012. Note: Electronic Article. [PubMed: 23029027] [Full Text: https://doi.org/10.1371/journal.pone.0045464]
Mozaffari-Jovin, S., Wandersleben, T., Santos, K. F., Will, C. L., Luhrmann, R., Wahl, M. C. Inhibition of RNA helicase Brr2 by the C-terminal tail of the spliceosomal protein Prp8. Science 341: 80-84, 2013. [PubMed: 23704370] [Full Text: https://doi.org/10.1126/science.1237515]
Nagase, T., Ishikawa, K., Suyama, M., Kikuno, R., Miyajima, N., Tanaka, A., Kotani, H., Nomura, N., Ohara, O. Prediction of the coding sequences of unidentified human genes. XI. The complete sequences of 100 new cDNA clones from brain which code for large proteins in vitro. DNA Res. 5: 277-286, 1998. [PubMed: 9872452] [Full Text: https://doi.org/10.1093/dnares/5.5.277]
Nguyen, T. H. D., Galej, W. P., Bai, X., Savva, C. G., Newman, A. J., Scheres, S. H. W., Nagai, K. The architecture of the spliceosomal U4/U6.U5 tri-snRNP. Nature 523: 47-52, 2015. [PubMed: 26106855] [Full Text: https://doi.org/10.1038/nature14548]
Zhao, C., Bellur, D. L., Lu, S., Zhao, F., Grassi, M. A., Bowne, S. J., Sullivan, L. S., Daiger, S. P., Chen, L. J., Pang, C. P., Zhao, K., Staley, J. P., Larsson, C. Autosomal-dominant retinitis pigmentosa caused by a mutation in SNRNP200, a gene required for unwinding of U4/U6 snRNAs. Am. J. Hum. Genet. 85: 617-627, 2009. [PubMed: 19878916] [Full Text: https://doi.org/10.1016/j.ajhg.2009.09.020]
Zhao, C., Lu, S., Zhou, X., Zhang, X., Zhao, K., Larsson, C. A novel locus (RP33) for autosomal dominant retinitis pigmentosa mapping to chromosomal region 2cen-q12.1. Hum. Genet. 119: 617-623, 2006. [PubMed: 16612614] [Full Text: https://doi.org/10.1007/s00439-006-0168-3]