Helix-loop-helix DNA-binding domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 23097242   102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMT 154
Cdd:pfam00010   1 RREAHNERERRRRDRINDAFDELRELLPTLPPDKKLSKAEILRLAIEYIKHLQ 53

basic helix-loop-helix (bHLH) domain found in Fer3-like protein (FERD3L), pancreas transcription factor 1 subunit alpha (PTF1A) and similar proteins; The family corresponds to a group of bHLH transcription factors, including FERD3L and PTF1A. FERD3L, also termed basic helix-loop-helix protein N-twist, or Class A basic helix-loop-helix protein 31 (bHLHa31), or nephew of atonal 3 (NATO3), or Neuronal twist (NTWIST), is expressed in the developing central nervous system (CNS). It regulates floor plate (FP) cells development. FP is a critical organizing center located at the ventral-most midline of the neural tube. FERD3L binds to the E-box and functions as inhibitor of transcription. PTF1A, also termed Class A basic helix-loop-helix protein 29 (bHLHa29), or pancreas-specific transcription factor 1a, or bHLH transcription factor p48, or p48 DNA-binding subunit of transcription factor PTF1 (PTF1-p48), is implicated in the cell fate determination in various organs. It binds to the E-box consensus sequence 5'-CANNTG-3' and plays a role in early and late pancreas development and differentiation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19686   1 QRQAANIRERKRMRSINDAFDGLRRHIPTFPYEKRLSKVDTLRLAIQYINFLTELL 56

basic helix-loop-helix (bHLH) domain found in pancreas transcription factor 1 subunit alpha (PTF1A) and similar proteins; PTF1A, also termed Class A basic helix-loop-helix protein 29 (bHLHa29), or pancreas-specific transcription factor 1a, or bHLH transcription factor p48, or p48 DNA-binding subunit of transcription factor PTF1 (PTF1-p48), is a bHLH transcription factor implicated in the cell fate determination in various organs. It binds to the E-box consensus sequence 5'-CANNTG-3' and plays a role in early and late pancreas development and differentiation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd11417   1 QRQAANLRERRRMQSINDAFEGLRSHIPTLPYEKRLSKVDTLRLAIGYINFLSELV 56

Helix-loop-helix DNA-binding domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 23097242   102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMT 154
Cdd:pfam00010   1 RREAHNERERRRRDRINDAFDELRELLPTLPPDKKLSKAEILRLAIEYIKHLQ 53

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 1 (ATOH1) and similar proteins; ATOH1, also termed Class A basic helix-loop-helix protein 14 (bHLHa14), or helix-loop-helix protein hATH-1 (hATH1), or Math1, or Cath1, is a proneural bHLH transcription factor that is essential for inner ear hair cell differentiation. It dimerizes with E47 and activates E-box (CANNTG) dependent transcription. ATOH1 is a mammalian homolog of the Drosophila melanogaster gene atonal and mouse atonal homolog 1 (Math1).

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLES 159
Cdd:cd19713   6 RRLAANARERRRMHGLNHAFDQLRNVIPSFNNDKKLSKYETLQMAQIYINALSELLQG 63

helix loop helix domain;

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|...
gi 23097242    107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLES 159
Cdd:smart00353   1 NARERRRRRKINEAFDELRSLLPTLPKNKKLSKAEILRLAIEYIKSLQEELQK 53

basic helix-loop-helix (bHLH) domain found in neurogenin (NGN) family; The NGN family includes three neural-specific bHLH transcription factors, NGN1-3, which may function at neuroblast selection genes during the development of several neuronal lineages. NGN-1, also termed Class A basic helix-loop-helix protein 6 (bHLHa6), or neurogenic basic-helix-loop-helix protein, or neurogenic differentiation factor 3 (NeuroD3), is a neural-specific bHLH transcription factor involved in the initiation of neuronal differentiation. NGN-2, also termed Class A basic helix-loop-helix protein 8 (bHLHa8), or protein atonal homolog 4 (ATOH4), is a neural-specific bHLH transcription factor required for sensory neurogenesis. NGN-3, also termed Class A basic helix-loop-helix protein 7 (bHLHa7), or protein atonal homolog 5 (ATOH5), is a neural-specific bHLH transcription factor expressed in the developing central nervous system and the embryonic pancreas. It is involved in neurogenesis and plays an important role in spermatogenesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd11428   1 RRLKANDRERNRMHNLNDALDALREVLPSFPDETKLTKIETLRFAHNYIWALSETLK 57

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 2 (NeuroD2) and similar proteins; NeuroD2, also termed Class A basic helix-loop-helix protein 1 (bHLHa1), or NeuroD-related factor (NDRF), is a neuronal calcium-dependent bHLH transcription factor that induces neuronal differentiation and promotes neuronal survival. It plays a central role in thalamocortical synaptic maturation. NeuroD2 mediates calcium-dependent transcription activation by binding to E box-containing promoter.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 23097242  91 RPKR----KRVITYAQ-------RQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLES 159
Cdd:cd19720  13 RPKKrgpkKRKMTKARlersklrRQKANARERNRMHDLNSALDNLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEILRS 92

basic helix-loop-helix (bHLH) domain found in twist-related protein 1 (TWIST1) and similar proteins; TWIST1, also termed Class A basic helix-loop-helix protein 38 (bHLHa38), or H-twist, is a bHLH transcriptional regulator that inhibits myogenesis by sequestrating E proteins, inhibiting trans-activation by MEF2, and inhibiting DNA-binding by MYOD1 through physical interaction. It also represses expression of proinflammatory cytokines such as TNFA and IL1B. In addition, TWIST1 is involved in cancer development and progression.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKrLSRIETLRLAIVYISFMTELLESCE 161
Cdd:cd11412  12 QRVMANVRERQRTQSLNEAFAALRKIIPTLPSDK-LSKIQTLKLAARYIDFLYQVLQSDE 70

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 7 (ATOH7) and similar proteins; ATOH7, also termed Class A basic helix-loop-helix protein 13 (bHLHa13), or helix-loop-helix protein hATH-5 (hATH5), or Math5, is a bHLH transcription factor involved in the differentiation of retinal ganglion cells.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLESCEK 162
Cdd:cd19714   8 RRLAANARERRRMQGLNTAFDRLRKVVPQWGQDKKLSKYETLQMALSYIMALTRILAEAER 68

basic helix-loop-helix (bHLH) domain found in neurogenin-2 (NGN-2) and similar proteins; NGN-2, also termed Class A basic helix-loop-helix protein 8 (bHLHa8), or protein atonal homolog 4 (ATOH4), is a neural-specific bHLH transcription factor required for sensory neurogenesis. It activates transcription by binding to the E box (5'-CANNTG-3').

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 23097242  98 ITYAQRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19717   6 IKKTRRVKANNRERNRMHNLNAALDSLREVLPTFPEDAKLTKIETLRFAHNYIWALSETL 65

basic helix-loop-helix (bHLH) domain found in achaete-scute complex-like (ASCL) family; The achaete-scute complex-like (ASCL, also known as achaete-scute complex homolog or ASH) family of bHLH transcription factors, ASCL1-5, have been implicated in cell fate specification and differentiation. They are critical for proper development of the nervous system. The deregulation of ASCL plays a key role in psychiatric and neurological disorders. ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete-scute homolog 1 (Mash1), is a neural-specific bHLH transcription factor that is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system. ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete-scute homolog 2 (Mash2), is a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves. ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is a bHLH transcription factor specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. The family also includes Drosophila melanogaster achaete-scute complex (AS-C) proteins, which consists of lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd11418   6 NERERRRVQAVNDAFDRLRQHVPYLKRRKKLSKVKTLRRAIEYIRHLQKLL 56

basic helix-loop-helix (bHLH) domain found in T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family; The TAL/LYL family includes a group of bHLH transcription factors (TAL1, TAL2 and LYL1) implicated in T cell acute leukaemia. They act as mediators of T cell leukaemogenesis. TAL-1, also termed Class A basic helix-loop-helix protein 17 (bHLHa17), or stem cell protein (SCL), or T-cell leukemia/lymphoma protein 5, is a hematopoietic-specific bHLH transcription factor that functions in embryonic and adult hematopoiesis in vertebrates. It is also required for embryonic vascular remodeling. It acts as a regulator of erythroid differentiation and binds to regulatory regions of a large cohort of erythroid genes as part of a complex with GATA-1, LMO2 and Ldb1. TAL-2, also termed Class A basic helix-loop-helix protein 19 (bHLHa19), is a bHLH transcription factor essential for the normal brain development. Lyl-1, also termed Class A basic helix-loop-helix protein 18 (bHLHa18), or lymphoblastic leukemia-derived sequence 1, is a proto-oncogenic bHLH transcription factor that plays an important role in hematopoietic stem cell function and is required for the late stages of postnatal angiogenesis to limit the formation of new blood vessels, notably by regulating the activity of the small GTPase Rap1. LYL-1 deficiency induces a stress erythropoiesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd11413   6 NTRERWRQQNVNGAFAELRKLIPTHPPDKKLSKNEILRLAMKYIKFLEKILE 57

basic helix-loop-helix (bHLH) domain found in muscle, intestine and stomach expression 1 (MIST-1) and similar proteins; MIST-1, also termed Class A basic helix-loop-helix protein 15 (bHLHa15), or Class B basic helix-loop-helix protein 8 (bHLHb8), is a bHLH transcription factor expressed in pancreatic acinar cells and other serous exocrine cells. It is essential for cytoskeletal organization and secretory activity. It also functions as a potent endoplasmic reticulum (ER) stress-inducible transcriptional regulator. MIST-1 is capable of binding to E-box (CANNTG) motifs as a homodimer or a heterodimer with E-proteins (E12 and E47) to regulate transcription.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMT 154
Cdd:cd19711   1 RRLESNERERQRMHKLNNAFQALREVIPHVRAEKKLSKIETLTLAKNYIKSLT 53

basic helix-loop-helix (bHLH) domain found in factor in the germline alpha (FIGLA) and similar proteins; FIGLA, also termed FIGalpha, or Class C basic helix-loop-helix protein 8 (bHLHc8), or folliculogenesis-specific basic helix-loop-helix protein, or transcription factor FIGa, is a germ-cell-specific bHLH transcription factor expressed abundantly in female and less so in male germ cells. It is essential for primordial follicle formation and expression of many genes required for folliculogenesis, fertilization and early embryonic survival. FIGLA knockout mice cannot form primordial follicles and lose oocytes rapidly after birth, whereas male gonads are unaffected.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 23097242 103 RQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd11422   1 RRVANARERERVRNLNSGFSKLRRIVPLIPRDRKPSKVDTLKGATEYIRLLQRILE 56

basic helix-loop-helix (bHLH) domain found in protein atonal homolog 8 (ATOH8) and similar proteins; ATOH8, also termed Class A basic helix-loop-helix protein 21 (bHLHa21), or helix-loop-helix protein hATH-6 (hATH6), is a bHLH shear-stress-responsive transcription factor expressed in activated satellite cells and proliferating myoblasts of human skeletal muscle tissue. It regulates endothelial cell proliferation, migration and tube-like structures formation. ATOH8 binds a palindromic (canonical) core consensus DNA sequence 5'-CANNTG- 3' known as an E-box element, possibly as a heterodimer with other bHLH proteins.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 23097242  98 ITYAQRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd11421   4 MTRQRRIEANARERTRVHTISAAFEALRKAVPSYSYNQKLSKLAILRIACSYILALARLAD 64

basic helix-loop-helix (bHLH) domain found in mesoderm posterior protein (Mesp) family; Mesp, a bHLH tissue specific transcription factor, acts as a key regulator of the cardiovascular transcriptional network by inducing directly and/or indirectly the expression of the majority of key cardiovascular transcription factors. The Mesp family includes two bHLH transcription factors, Mesp1 and Mesp2. Mesp1, also termed Class C basic helix-loop-helix protein 5 (bHLHc5), promotes cardiovascular differentiation during embryonic development and embryonic stem cell differentiation. Mesp2, also termed Class C basic helix-loop-helix protein 6 (bHLHc6), plays an important role in somitogenesis. The family also includes mesogenin-1 (Msgn1) and similar proteins. Msgn1, also termed paraxial mesoderm-specific mesogenin1, or pMesogenin1 (pMsgn1), is a bHLH transcription factor required for maturation and segmentation of paraxial mesoderm. It may regulate the expression of T-box transcription factors essential for mesoderm formation and differentiation.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPT--FAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd11425   1 QRQLANERERLRMRTLADALGELRQHLPPsvAPKGKRLSKIQTLKYAIRYIGYLGNVLQ 59

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster helix loop helix protein 3B (dHLH3B) and similar proteins; Drosophila HLH3B is an uncharacterized bHLH transcription factor that belongs to the T-cell acute lymphocytic leukemia protein/ lymphoblastic leukemia-derived sequence (TAL/LYL) family.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd19708   1 RRMFTNSRERWRQQNVNGAFAELRKLVPTHPPDKKLSKNEILRLAIKYIRLLSNVLE 57

basic helix-loop-helix (bHLH) domain found in achaete-scute-like proteins, ASCL3-5, and similar proteins; This subfamily includes three ASCL family of transcription factors, ASCL-3, ASCL-4 and ASCL-5. ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis. ASCL-4, also termed Class A basic helix-loop-helix protein 44 (bHLHa44), or achaete-scute homolog 4 (ASH-4), or Hash4, may be involved in skin development. ASCL-5, also termed Class A basic helix-loop-helix protein 47 (bHLHa47), or achaete-scute homolog 5 (ASH-5), is an uncharacterized bHLH transcription factor that is close related to ASCL-3 and ASCL-4.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19724   6 NERERQRVRCVNEGYARLRRHLPLENKDKRLSKVETLRAAIRYIKHLQELL 56

basic helix-loop-helix (bHLH) domain found in protein lyl-1 and similar proteins; Lyl-1, also termed Class A basic helix-loop-helix protein 18 (bHLHa18), or lymphoblastic leukemia-derived sequence 1, is a proto-oncogenic bHLH transcription factor involved in T-cell acute lymphoblastic leukemia. It plays an important role in hematopoietic stem cell function and is required for the late stages of postnatal angiogenesis to limit the formation of new blood vessels, notably by regulating the activity of the small GTPase Rap1. LYL-1 deficiency induces a stress erythropoiesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 23097242 101 AQRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19705   5 ARRVFTNSRERWRQQNVNGAFAELRKLIPTHPPDKKLSKNEILRLAMKYIDFLVTLL 61

basic helix-loop-helix (bHLH) domain found in scleraxis and similar proteins; Scleraxis, also termed SCX, or Class A basic helix-loop-helix protein 41 (bHLHa41), or Class A basic helix-loop-helix protein 48 (bHLHa48), is a bHLH transcription factor that is expressed in sclerotome limb bud cranial and body wall mesenchyme, pericardium and heart valves, ligaments and tendons. It is required for tendon formation ligaments, connective tissue, the diaphragm, and testis development. Scleraxis plays a central role in promoting fibroblast proliferation and matrix synthesis during the embryonic development of tendons.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd18951   4 QRHTANARERDRTNSVNTAFTALRTLIPTEPADRKLSKIETLRLASSYISHLGNVL 59

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 3 (ASCL-3) and similar proteins; ASCL-3, also termed Class A basic helix-loop-helix protein 42 (bHLHa42), or bHLH transcriptional regulator Sgn-1, or achaete-scute homolog 3 (ASH-3), is a bHLH transcription factor specifically localized in the duct cells of the salivary glands. It may act as transcriptional repressor that inhibits myogenesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19745   9 NERERQRVKCVNEGYAKLRRHLPQEYSEKRLSKVETLRAAIKYIKHLQSVL 59

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 5 (ASCL-5) and similar proteins; ASCL-5, also termed Class A basic helix-loop-helix protein 47 (bHLHa47), or achaete-scute homolog 5 (ASH-5), is an uncharacterized bHLH transcription factor that belongs to AS-C (achaete, scute, lethal of scute, and asense) family.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 23097242 104 QAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19747   8 QKRNERERQRVKCVNEGYARLRDHLPGAMAEKRLSKVETLRAAIRYIKYLQDLL 61

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster achaete-scute complex (AS-C) proteins, achaete-scute-like proteins, ASCL1-2, and similar proteins; This subfamily includes Drosophila melanogaster AS-C proteins and two ASCL family of transcription factors, ASCL-1 and ASCL-2. Drosophila melanogaster AS-C proteins includes lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation. ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete scute homolog 1 (Mash1), is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system. ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete scute homolog 2 (Mash2), is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19723   6 NERERNRVKLVNLGFATLREHVPNGRANKKMSKVETLRSAVEYIRQLQQLL 56

basic helix-loop-helix (bHLH) domain found in musculin, transcription factor 21 (TCF-21) and similar proteins; The family includes two bHLH transcription factors, musculin and transcription factor 21 (TCF-21). Musculin, also termed activated B-cell factor 1 (ABF-1), or Class A basic helix-loop-helix protein 22 (bHLHa22), is a bHLH transcription factor expressed in activated B lymphocytes. It acts as a transcription repressor capable of inhibiting the transactivation capability of TCF3/E47. Musculin may play a role in regulating antigen-dependent B-cell differentiation. The mouse homolog, musculin, is suggested to be a repressor of myogenesis that is expressed in developing muscle and in the spleen. TCF-21, also termed capsulin, or Class A basic helix-loop-helix protein 23 (bHLHa23), or epicardin, or podocyte-expressed 1 (Pod-1), is a bHLH transcription factor expressed specifically in mesodermally-derived cells that surround the epithelium of the developing gastrointestinal, genitourinary and respiratory systems during mouse embryogenesis. It may play a role in the specification or differentiation of one or more subsets of epicardial cell types.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd11423   1 QRNAANARERARMRVLSKAFSRLKTTLPWVPPDTKLSKLDTLRLAASYIAHLRQIL 56

basic helix-loop-helix (bHLH) domain found in musculin and similar proteins; Musculin, also termed activated B-cell factor 1 (ABF-1), or Class A basic helix-loop-helix protein 22 (bHLHa22), is a bHLH transcription factor expressed in activated B lymphocytes. It acts as a transcription repressor capable of inhibiting the transactivation capability of TCF3/E47. Musculin may play a role in regulating antigen-dependent B-cell differentiation. The mouse homolog, musculin, is suggested to be a repressor of myogenesis that is expressed in developing muscle and in the spleen. Musculin heterodimerizes with products of the E2A gene.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 23097242 101 AQRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd19703   3 SQRNAANARERARMRVLSKAFSRLKTSLPWVPPDTKLSKLDTLRLASSYIAHLRQLLQ 60

basic helix-loop-helix (bHLH) domain found in the mesoderm posterior protein (Mesp) family; Mesp, a bHLH tissue specific transcription factor, acts as a key regulator of the cardiovascular transcriptional network by inducing directly and/or indirectly the expression of the majority of key cardiovascular transcription factors. The Mesp family includes two bHLH transcription factors, Mesp1 and Mesp2. Mesp1, also termed Class C basic helix-loop-helix protein 5 (bHLHc5), promotes cardiovascular differentiation during embryonic development and embryonic stem cell differentiation. Mesp2, also termed Class C basic helix-loop-helix protein 6 (bHLHc6), plays an important role in somitogenesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVP--TFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd18938   1 QRQSASEREKLRMRDLAKALHNLRRYLPpsVAPAGQSLTKIETLRLTIRYISHLSAQL 58

basic helix-loop-helix (bHLH) domain found in transcription factor 21 (TCF-21) and similar proteins; TCF-21, also termed capsulin, or Class A basic helix-loop-helix protein 23 (bHLHa23), or epicardin, or podocyte-expressed 1 (Pod-1), is a bHLH transcription factor expressed specifically in mesodermally-derived cells that surround the epithelium of the developing gastrointestinal, genitourinary and respiratory systems during mouse embryogenesis. It may play a role in the specification or differentiation of one or more subsets of epicardial cell types.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19704   4 QRNAANARERARMRVLSKAFSRLKTTLPWVPPDTKLSKLDTLRLASSYIAHLRQIL 59

basic helix-loop-helix (bHLH) domain found in muscle-specific regulatory factor 4 (MRF4) and similar proteins; MRF4, also termed Class C basic helix-loop-helix protein 4 (bHLHc4), or myogenic factor 6 (Myf-6), is a bHLH transcription factor associated with myogenesis. It plays a role in skeletal muscle differentiation.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRK-VPTfaYEKRLSRIETLRLAIVYISFMTELLESCEKKE 164
Cdd:cd18934   2 RRKAATLRERRRLKKINEAFEALKRRtVPN--PNQRLPKVEILRSAINYIEKLQDLLHSLDQQE 63

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 1 (ASCL-1) and similar proteins; ASCL-1, also termed Class A basic helix-loop-helix protein 46 (bHLHa46), or achaete-scute homolog 1 (ASH-1), or mammalian achaete scute homolog 1 (Mash1), is a neural-specific bHLH transcription factor that is expressed in subsets of neural progenitors in both the central and peripheral nervous system. It plays a key role in neuronal differentiation and specification in the nervous system.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 23097242 102 QRQAA----NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd19742   1 QQPAAvarrNERERNRVKLVNMGFATLREHVPNGAANKKMSKVETLRSAVEYIRALQQLLD 61

basic helix-loop-helix (bHLH) domain found in Oligodendrocyte lineage genes (OLIG) family of transcription factors; The OLIG family includes three bHLH transcription factors, Oligo1-3, which are expressed in both the developing and mature central nervous system. Oligo1 and Oligo2 are expressed in a nervous tissue-specific manner, but Oligo3 is found mainly in non-neural tissues. Oligo (also known as Olig) have key roles in the specification of motor neurons, dorsal interneurons, and oligodendrocytes. Oligo1, also termed Class B basic helix-loop-helix protein 6 (bHLHb6), or Class E basic helix-loop-helix protein 21 (bHLHe21), promotes formation and maturation of oligodendrocytes, especially within the brain. Oligo2, also termed Class B basic helix-loop-helix protein 1 (bHLHb1), or Class E basic helix-loop-helix protein 19 (bHLHe19), or protein kinase C-binding protein 2, or protein kinase C-binding protein RACK17, is required for oligodendrocyte and motor neuron specification in the spinal cord, as well as for the development of somatic motor neurons in the hindbrain. It cooperates with OLIG1 to establish the MN progenitors (pMN) domain of the embryonic neural tube. Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is expressed in the ventricular zone of the dorsal alar plate of the hindbrain and involved in regulating the development of dorsal and ventral spinal cord. It may determine the distinct specification program of class A neurons in the dorsal part of the spinal cord and suppress specification of class B neurons. This family also includes two OLIG-related bHLH transcription factors, bHLHe22 and bHLHe23. bHLHe22, also termed Class B basic helix-loop-helix protein 5 (bHLHb5), or trinucleotide repeat-containing gene 20 protein, is a neural-specific transcriptional repressor that is expressed in both excitatory (unipolar brush cells) and inhibitory neurons (cartwheel cells) of the dorsal cochlear nucleus (DCN) during development. It is important for the proper development and/or survival of a number of neural cell types. bHLHe23, also termed Class B basic helix-loop-helix protein 4 (bHLHb4), is expressed in rod bipolar cells and is required for rod bipolar cell maturation. bHLHe23 have roles in spinal interneuron differentiation by mechanisms linked to the Notch signaling pathway. It modulates the expression of genes required for the differentiation and/or maintenance of pancreatic and neuronal cell types.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 23097242 103 RQAANIRERKRMFNLNEAFDQLRRKVPTFAYE--KRLSRIETLRLAIVYISFMTELLES 159
Cdd:cd11429   1 RLKINSRERKRMHDLNSALDGLRSVMPYAQGPsvRKLSKIATLLLARNYILMLTQALEE 59

basic helix-loop-helix (bHLH) domain found in myoblast determination protein 1 (MYOD1) and similar proteins; MYOD1, also termed Class C basic helix-loop-helix protein 1 (bHLHc1), or myogenic factor 3 (Myf-3), is a bHLH transcriptional activator that promotes transcription of muscle-specific target genes and plays a role in muscle differentiation. Together with Myf-5 and MYOG, MYOD1 co-occupies muscle-specific gene promoter core region during myogenesis.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAyEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd18936   6 RRKAATMRERRRLSKVNEAFETLKRCTSTNP-NQRLPKVEILRNAIRYIESLQALL 60

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 2 (ASCL-2) and similar proteins; ASCL-2, also termed achaete-scute homolog 2 (ASH-2), or Class A basic helix-loop-helix protein 45 (bHLHa45), or mammalian achaete scute homolog 2 (Mash2), is a bHLH transcription factor that is involved in Schwann cell differentiation and control of proliferation in adult peripheral nerves.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19743   8 NERERNRVKLVNLGFAALRQHVPQGGASKKMSKVETLRSAVEYIRALQRLL 58

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster achaete-scute complex (AS-C) proteins and similar proteins; Drosophila melanogaster AS-C proteins includes lethal of scute (also known as achaete-scute complex protein T3 or AST3), scute (also known as achaete-scute complex protein T4 or AST4), achaete (also known as achaete-scute complex protein T5 or AST5), and asense (also known as achaete-scute complex protein T8 or AST8). They are involved in the determination of the neuronal precursors in the peripheral nervous system and the central nervous system, as well as in sex determination and dosage compensation.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYE-----------KRLSRIETLRLAIVYISFMTELL 157
Cdd:cd19744   6 NARERNRVKQVNNGFAILRQHIPQSVIEdltagggrgksKKLSKVDTLRMAVEYIRRLQKLL 67

basic helix-loop-helix (bHLH) domain found in mesogenin-1 (Msgn1) and similar proteins; Msgn1, also termed paraxial mesoderm-specific mesogenin1, or pMesogenin1 (pMsgn1), is a bHLH transcription factor required for maturation and segmentation of paraxial mesoderm. It may regulate the expression of T-box transcription factors essential for mesoderm formation and differentiation.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 23097242  95 KRVITYAQRQAANIRERKRMFNLNEAFDQLRRKVPTfAYEKR---LSRIETLRLAIVYISFMTELLE 158
Cdd:cd18939   1 KVKMSAQRRRKASEREKLRMRTLAEALHTLRNYLPP-VYSQRgqpLTKIQTLKCTIQYISELSGLLN 66

basic helix-loop-helix (bHLH) domain found in myogenin (MYOG) and similar proteins; MYOG, also termed Class C basic helix-loop-helix protein 3 (bHLHc3), or myogenic factor 4 (Myf-4), is a bHLH transcriptional activator that promotes transcription of muscle-specific target genes and plays a role in muscle differentiation, cell cycle exit and muscle atrophy.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVpTFAYEKRLSRIETLRLAIVYISFMTELLES 159
Cdd:cd18935   2 RRRAATLREKRRLKKVNEAFEALKRST-LLNPNQRLPKVEILRSAIQYIERLQALLSS 58

basic helix-loop-helix (bHLH) domain found in transcription factor 23 (TCF-23) and similar proteins; TCF-23, also termed Class A basic helix-loop-helix protein 24 (bHLHa24), is a bHLH transcription factor that is essential for progesterone-dependent decidualization. The mouse homolog is also called ovary, uterus and testis protein (OUT), which is expressed predominantly in the reproductive organs such as the uterus, ovary and testis. It shows an Id-like inhibitory activity and functions as a negative regulator of bHLH factors through the formation of a functionally inactive heterodimeric complex. OUT inhibits the formation of TCF3 and MYOD1 homodimers and heterodimers, but lacks DNA binding activity. OUT is involved in the regulation or modulation of smooth muscle contraction of the uterus during pregnancy and particularly around the time of delivery. It also plays a role in the inhibition of myogenesis. Unlike typical bHLH factors, OUT proteins do not bind E-box (CANNTG) or N-box DNA sequences and inhibit DNA binding of homo- and heterodimers consisting of E12 and MyoD in gel mobility shift assays.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 23097242 109 RERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd19709   7 RERSRVRTLRQAFLALQAALPSVPPDTKLSKLDVLVLATSYIAHLTRTLD 56

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in protein Max and similar proteins; Max, also termed Class D basic helix-loop-helix protein 4 (bHLHd4), or Myc-associated factor X, is a bHLHZip transcription regulator that forms a sequence-specific DNA-binding protein complex with MYC or MAD which recognizes the core sequence 5'-CAC[GA]TG-3'. The MYC:MAX complex is a transcriptional activator, whereas the MAD:MAX complex is a transcriptional repressor. Max homodimer bind DNA but is transcriptionally inactive. Targeted deletion of max results in early embryonic lethality in mice.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*...
gi 23097242 107 NIRERKRMFNLNEAFDQLRRKVPTFAYEKrLSRIETLRLAIVYISFMT 154
Cdd:cd11406   6 NALERKRRDHIKDSFHSLRDSVPSLQGEK-ASRAQILKKATEYIQYMR 52

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in the Myc family; The Myc family is a member of the bHLHzip family of transcription factors that play important roles in the control of normal cell proliferation, growth, survival and differentiation. All Myc isoforms contain two independently functioning polypeptide chain regions: N-terminal transactivating residues and a C-terminal bHLHzip segment. The bHLHzip family of bHLH transcription factors are characterized by a highly conserved N-terminal basic region that may bind DNA at a consensus hexanucleotide sequence known as the E-box (CANNTG) followed by HLH and leucine zipper motifs that may interact with other proteins to form homo- and heterodimers. Myc heterodimerizes with Max enabling specific binding to E-box DNA sequences in the promoters of target genes. The Myc proto-oncoprotein family includes at least five different functional members: c-, N-, L-, S- and B-Myc (which is lacking the bHLH domain).

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMT 154
Cdd:cd11400   1 KRRLHNVLERQRRNDLKNSFEKLRDLVPELADNEKASKVVILKKATEYIKQLQ 53

basic helix-loop-helix (bHLH) domain found in DNA-binding protein inhibitor ID4 and similar proteins; ID4, also termed Class B basic helix-loop-helix protein 27 (bHLHb27), or inhibitor of DNA binding 4, or inhibitor of differentiation 4, is a dominant negative helix-loop-helix (dnHLH) transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the bHLH transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. It plays a role in adipose cell differentiation.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 23097242 115 FNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYISFMTELLES 159
Cdd:cd19694   9 YDMNDCYSRLKRLVPTIPPNKKVSKVEILQHVIDYILDLQLALET 53

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factor 1 (Oligo1) and similar proteins; Oligo1, also termed Class B basic helix-loop-helix protein 6 (bHLHb6), or Class E basic helix-loop-helix protein 21 (bHLHe21), is a bHLH transcription factor that promotes formation and maturation of oligodendrocytes, especially within the brain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 23097242 103 RQAANIRERKRMFNLNEAFDQLRRKVPTFAYE-------KRLSRIETLRLAIVYISFMTELLE 158
Cdd:cd18942   7 RRKINSRERKRMQDLNLAMDALREVILPYSAAhcqsspgRKLSKIATLLLARNYILLLGSSLQ 69

basic helix-loop-helix (bHLH) domain found in DNA-binding protein inhibitor ID2 and similar proteins; ID2, also termed Class B basic helix-loop-helix protein 26 (bHLHb26), or inhibitor of DNA binding 2, or inhibitor of differentiation 2, is a dominant negative helix-loop-helix (dnHLH) transcriptional regulator (lacking a basic DNA binding domain) which negatively regulates the bHLH transcription factors by forming heterodimers and inhibiting their DNA binding and transcriptional activity. It has been implicated in the regulation of cell proliferation and differentiation in myogenesis, neurogenesis, and/or hematopoiesis.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 23097242 114 MFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYI 150
Cdd:cd19692  19 LYNMNDCYSKLKELVPSIPQNKKVSKMEILQHVIDYI 55

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in MLX-interacting protein (MLXIP) and similar proteins; MLXIP, also termed Class E basic helix-loop-helix protein 36 (bHLHe36), or transcriptional activator MondoA, is a bHLHZip transcriptional activator that binds DNA as a heterodimer with Mlx. It binds to the canonical E box sequence 5'-CACGTG-3' and plays a role in transcriptional activation of glycolytic target genes. MLXIP is most highly expressed in skeletal muscle and functions as an indirect glucose sensor, by sensing glucose 6-phosphate and shuttling between the nucleus and the cytoplasm.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 23097242 102 QRQAANIRERKRMFNLNEAFDQLRRKVPTFAYEKRLSRIETLRLAIVYIS 151
Cdd:cd19688   3 RRMKHISAEQKRRFNIKICFDTLNSLVSTLKNSKPISNAITLQKTVEYIA 52