helix loop helix domain;

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|....*.
gi 326205341    53 MQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAE 98
Cdd:smart00353   8 RRKINEAFDELRSLLPTLPKNKKLSKAEILRLAIEYIKSLQEELQK 53

basic helix-loop-helix (bHLH) domain found in protein atonal homologs ATOH1, ATOH7 and similar proteins; The family includes ATOH1 and ATOH7. 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). 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. The family also includes protein Amos (also termed absent MD neurons and olfactory sensilla protein, or reduced olfactory organs protein, or rough eye protein). It is a bHLH transcription factor that promotes multiple dendritic neuron formation in the Drosophila peripheral nervous system.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11430    9 ERRRMNGLNRAFDQLRSVVPSIGNDKKLSKYETLQMAQIYIETLSELL 56

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
                 ....*....|....*....|....*....|....*....|....*...
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19713   14 ERRRMHGLNHAFDQLRNVIPSFNNDKKLSKYETLQMAQIYINALSELL 61

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor (NeuroD) family; The NeuroD family includes NeuroD1, NeuroD2, NeuroD4 and NeuroD6. NeuroD1, also termed Class A basic helix-loop-helix protein 3 (bHLHa3), is a neuronal bHLH transcription factor involved in the development and maintenance of the endocrine pancreas and neuronal elements. It acts as an essential regulator of glutamatergic neuronal differentiation. Loss of NeuroD1 causes ataxia, cerebellar hypoplasia, sensorineural deafness, and severe retinal dystrophy in mice. 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. NeuroD4, also termed Class A basic helix-loop-helix protein 4 (bHLHa4), or protein atonal homolog 3 (ATH-3), or Atoh3, or Math-3, is a bHLH transcriptional activator that mediates neuronal differentiation. NeuroD6, also termed Class A basic helix-loop-helix protein 2 (bHLHa2), or protein atonal homolog 2 (ATH-2), or Atoh2, or Math2, or Nex1, is a neurogenic bHLH transcription factor involved in neuronal development, differentiation, and survival in Alzheimer's disease (AD) brains of both cohorts. It plays an integrative role in coordinating increase in mitochondrial mass with cytoskeletal remodeling, suggesting that it may act as a co-regulator of neuronal differentiation and energy metabolism.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 326205341  51 RRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11427   10 NRMHGLNDALDNLRKVVPCYSKTQKLSKIETLRLARNYIWALSEIL 55

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
                 ....*....|....*....|....*....|....*....|...
gi 326205341  54 QGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11418   14 QAVNDAFDRLRQHVPYLKRRKKLSKVKTLRRAIEYIRHLQKLL 56

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
                 ....*....|....*....|....*....|....*....|....*..
gi 326205341  50 RRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19686   10 RKRMRSINDAFDGLRRHIPTFPYEKRLSKVDTLRLAIQYINFLTELL 56

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 4 (NeuroD4) and similar proteins; NeuroD4, also termed Class A basic helix-loop-helix protein 4 (bHLHa4), or protein atonal homolog 3 (ATH-3), or Atoh3, or Math-3, is a bHLH transcriptional activator that mediates neuronal differentiation.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 326205341  51 RRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19721   40 SRMHGLNDALDNLRRVMPCYSKTQKLSKIETLRLARNYIWALSEVL 85

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
                 ....*....|....*....|....*....|....*....|.
gi 326205341  56 LNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11422   15 LNSGFSKLRRIVPLIPRDRKPSKVDTLKGATEYIRLLQRIL 55

basic helix-loop-helix (bHLH) domain found in neurogenic differentiation factor 1 (NeuroD1) and similar proteins; NeuroD1, also termed Class A basic helix-loop-helix protein 3 (bHLHa3), is a neuronal bHLH transcription factor involved in the development and maintenance of the endocrine pancreas and neuronal elements. It acts as an essential regulator of glutamatergic neuronal differentiation. Loss of NeuroD1 causes ataxia, cerebellar hypoplasia, sensorineural deafness, and severe retinal dystrophy in mice.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 326205341  33 GRLESAARRRLAANARERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19719   20 ARLERFKMRRMKANARERNRMHGLNAALDNLRKVVPCYSKTQKLSKIETLRLAKNYIWALSEIL 83

basic helix-loop-helix (bHLH) domain found in Fer3-like protein (FERD3L) and similar proteins; 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 a bHLH transcription factor 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11415   17 ERRRMFNLNEAFDKLRKKVPTFAYEKRLSRIETLRLAIVYISFMTDLL 64

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
                 ....*....|....*....|....*....|....*....|...
gi 326205341  56 LNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAE 98
Cdd:cd19743   18 VNLGFAALRQHVPQGGASKKMSKVETLRSAVEYIRALQRLLGE 60

basic helix-loop-helix (bHLH) domain found in T-cell acute lymphocytic leukemia protein 2 (TAL-2) and similar proteins; TAL-2, also termed Class A basic helix-loop-helix protein 19 (bHLHa19), is a bHLH transcription factor essential for the normal brain development. It has been implicated in T-cell acute lymphoblastic leukemia.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 326205341  54 QGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAEAE 100
Cdd:cd19707   15 QNVNSAFAELRKLIPTHPPDKKLSKNEILRLAMKYINFLVKLLGDQG 61

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
                 ....*....|....*....|....*....|....*....|....*....
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILA 97
Cdd:cd11428    9 ERNRMHNLNDALDALREVLPSFPDETKLTKIETLRFAHNYIWALSETLK 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
                 ....*....|....*....|....*....|....*....|....*...
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19711    9 ERQRMHKLNNAFQALREVIPHVRAEKKLSKIETLTLAKNYIKSLTTTI 56

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
                 ....*....|....*....|....*....|....*....|....*....|..
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAEAE 100
Cdd:cd19717   18 ERNRMHNLNAALDSLREVLPTFPEDAKLTKIETLRFAHNYIWALSETLRLAD 69

basic helix-loop-helix (bHLH) domain found in muscle, intestine and stomach expression 1 (MIST-1) family; 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. The family also includes Drosophila melanogaster protein dimmed and similar proteins. Dimmed, also termed DIMM, is a bHLH transcription factor that regulates neurosecretory (NS) cell function and neuroendocrine cell fate in Drosophila.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11426    9 ERLRMHQLNDAFQALREVIPHVRSERKLSKIETLTLAKNYIKSLTNMI 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
                 ....*....|....*....|....*....|....*....|....*
gi 326205341  54 QGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAE 98
Cdd:cd19705   19 QNVNGAFAELRKLIPTHPPDKKLSKNEILRLAMKYIDFLVTLLRD 63

basic helix-loop-helix (bHLH) domain found in heart- and neural crest derivatives-expressed protein 1 (HAND1) and similar proteins; HAND1, also termed Class A basic helix-loop-helix protein 27 (bHLHa27), or extraembryonic tissues, heart, autonomic nervous system and neural crest derivatives-expressed protein 1 (eHAND), is a bHLH transcription factor that plays an essential role in both trophoblast-giant cells differentiation and in cardiac morphogenesis.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 326205341  54 QGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAE 98
Cdd:cd18952   15 ESINSAFAELRECIPNVPADTKLSKIKTLRLATSYIAYLMDVLAK 59

basic helix-loop-helix (bHLH) domain found in scleraxis, transcription factor 15 (TCF-15) and similar proteins; The family includes scleraxis and transcription factor 15 (TCF-15). 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. TCF-15, also termed Class A basic helix-loop-helix protein 40 (bHLHa40), or paraxis, or protein bHLH-EC2, is a bHLH transcription factor expressed in caudal lateral and paraxial mesoderm dermomyotome and sclerotome fore limb buds during embryo development. It may function as an early transcriptional regulator involved in the patterning of the mesoderm and in lineage determination of cell types derived from the mesoderm.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 326205341  48 RERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11465    7 RERDRTHSVNSAFTALRTLIPTEPADRKLSKIETLRLASSYISHLATVL 55

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
                 ....*....|....*....|....*....|....*....|....*..
gi 326205341  50 RRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11417   10 RRRMQSINDAFEGLRSHIPTLPYEKRLSKVDTLRLAIGYINFLSELV 56

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
                 ....*....|....*....|....*....|....*....|....*...
gi 326205341  56 LNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAEAERFG 103
Cdd:cd18951   19 VNTAFTALRTLIPTEPADRKLSKIETLRLASSYISHLGNVLLVGEACG 66

basic helix-loop-helix (bHLH) domain found in Caenorhabditis elegans Helix-loop-helix protein 13 (HLH13) and similar proteins; Caenorhabditis elegans HLH13, also termed Fer3-like protein, or nephew of atonal 3, is a bHLH transcription factor that plays a role in the negative regulation of exit from L1 arrest and dauer diapause dependent on IIS signaling (insulin and insulin-like growth factor (IGF) signaling).

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 326205341  49 ERRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11416   13 ERKRMLSINSAFEELRCHVPTFPYEKRLSKIDTLRLAIAYIALLRDIL 60

basic helix-loop-helix (bHLH) domain found in helix-loop-helix protein 1 (HEN-1) and similar proteins; HEN-1, also termed nescient helix-loop-helix 1 (Nhlh1), or Class A basic helix-loop-helix protein 35 (bHLHa35), or nescient helix loop helix 1 (NSCL-1), is a neuron-specific bHLH transcription factor that may serve as DNA-binding protein and may be involved in the control of cell-type determination, possibly within the developing nervous system.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 326205341  53 MQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19701   28 VEAFNVAFAELRKLLPTLPPDKKLSKIEILRLAICYISYLNHVL 71

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
                 ....*....|....*....|....*....|....*..
gi 326205341  56 LNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMAL 92
Cdd:cd19694   11 MNDCYSRLKRLVPTIPPNKKVSKVEILQHVIDYILDL 47

basic helix-loop-helix (bHLH) domain found in achaete-scute-like protein 4 (ASCL-4) and similar proteins; ASCL-4, also termed Class A basic helix-loop-helix protein 44 (bHLHa44), or achaete-scute homolog 4 (ASH-4), or Hash4, is a bHLH transcriptional regulator that may be involved in skin development.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 326205341  56 LNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19746   23 VNEGYARLREHLPQELADKRLSKVETLRAAIDYIKHLQELL 63

basic helix-loop-helix (bHLH) domain found in helix-loop-helix protein 2 (HEN-2) and similar proteins; HEN-2, also termed nescient helix-loop-helix 2 (Nhlh2), or Class A basic helix-loop-helix protein 34 (bHLHa34), or nescient helix loop helix 2 (NSCL-2), is a neuron-specific bHLH transcription factor that may serve as DNA-binding protein and may be involved in the control of cell-type determination, possibly within the developing nervous system.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 326205341  53 MQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19702   28 VEAFNLAFAELRKLLPTLPPDKKLSKIEILRLAICYISYLNHVL 71

basic helix-loop-helix (bHLH) domain found in ovary, uterus and testis protein (OUT) family; The OUT family includes transcription factor 23 (TCF-23), transcription factor 24 (TCF-24) 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. TCF-24 is an uncharacterized bHLH transcription factor that shows high sequence similarity with TCF-23.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 326205341  53 MQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11424   12 VRTLRTAFQSLQRALPAVPPDTKLSKLDVLLLASRYIAHLTRKL 55

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
                 ....*....|....*....|....*....|....*....|....*....
gi 326205341  50 RRRMQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRILAE 98
Cdd:cd19703   13 RARMRVLSKAFSRLKTSLPWVPPDTKLSKLDTLRLASSYIAHLRQLLQE 61

basic helix-loop-helix (bHLH) domain found in the DNA-binding protein inhibitor (ID) family; The ID family includes a dominant negative group of helix-loop-helix (dnHLH) proteins, ID1-4, that are negative regulators of bHLH transcription factors. They contain the HLH-dimerization domain but lack the basic domain necessary for DNA-binding. ID proteins inhibit binding to DNA and transcriptional transactivation by heterodimerization with bHLH proteins. They also interact with many non-bHLH proteins in complex networks. ID proteins have been implicated in regulating gene expression as well as cell-cycle progression. Whereas ID-1, ID-2 and ID-3, are generally considered as tumor promoters, ID4 on the contrary has emerged as a tumor suppressor.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|
gi 326205341  53 MQGLntaFDRLRRVVPQWGQDKKLSKYETLQMALSYIMAL 92
Cdd:cd19684    8 MQDC---YSKLKELVPTIPQNKKVSKVEILQHVIDYILDL 44

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
                 ....*....|....*....|....*....|....*....|....*....|..
gi 326205341  56 LNTAFDRLRRVVPQW-----------GQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19744   16 VNNGFAILRQHIPQSviedltagggrGKSKKLSKVDTLRMAVEYIRRLQKLL 67

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 326205341  56 LNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMAL 92
Cdd:cd19692   22 MNDCYSKLKELVPSIPQNKKVSKMEILQHVIDYILDL 58

basic helix-loop-helix (bHLH) domain found in Class E basic helix-loop-helix protein bHLHe22, bHLHe23 and similar proteins; The family 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.

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                 ....*....|....*....|....*....|....*....|....*....|...
gi 326205341  52 RMQGLNTAFDRLRRVVPqWGQD---KKLSKYETLQMALSYIMALTRILAEAER 101
Cdd:cd11468   11 RMHDLNDALDDLRAVIP-YAHSpsvRKLSKIATLLLAKNYILMQARAIEELRR 62

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in MLX-interacting protein (MLXIP), MLX-interacting protein-like (MLXIPL) and similar proteins; The family includes MLXIP and MLXIPL. 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. MLXIPL, also termed carbohydrate-responsive element-binding protein (ChREBP), or Class D basic helix-loop-helix protein 14 (bHLHd14), or MLX interactor, or WS basic-helix-loop-helix leucine zipper protein (WS-bHLH), or Williams-Beuren syndrome chromosomal region 14 protein (WBSCR14), is a bHLHZip transcriptional factor integral to the regulation of glycolysis and lipogenesis in the liver. It forms heterodimers with the bHLHZip protein Mlx to bind the DNA sequence 5'-CACGTG-3'.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 326205341  56 LNTAFDRLRRVVPQWGQ--DKKLSKYETLQMALSYIMALTR----ILAEAERFGSE 105
Cdd:cd11405   18 IKSGFDTLQSLIPSLGQnpNQKVSKAAMLQKAAEYIKSLKRerqqMQEEAEQLRQE 73

basic helix-loop-helix (bHLH) domain found in twist-related protein 2 (TWIST2) and similar proteins; TWIST2, also termed Class A basic helix-loop-helix protein 39 (bHLHa39), or Dermis-expressed protein 1, or Dermo-1, is a bHLH transcription factor that regulates the development of mesenchymal tissues and plays a critical role in embryogenesis. It binds to the E-box consensus sequence 5'-CANNTG-3' as a heterodimer and inhibits transcriptional activation by MYOD1, MYOG, MEF2A and MEF2C.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 326205341  48 RERRRMQGLNTAFDRLRRVVPQWGQDkKLSKYETLQMALSYIMALTRILAEAE 100
Cdd:cd19700   24 RERQRTQSLNEAFAALRKIIPTLPSD-KLSKIQTLKLAARYIDFLYQVLQSDE 75

basic helix-loop-helix (bHLH) domain found in transcription factor 24 (TCF-24) and similar proteins; TCF-24 is an uncharacterized bHLH transcription factor that shows high sequence similarity with TCF-23.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 326205341  53 MQGLNTAFDRLRRVVPQWGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd19710   13 VQTLRSAFLELQRTLPSVPPDTKLSKLDVLVLATTYIAHLMRTL 56

basic Helix-Loop-Helix-zipper (bHLHzip) domain found in sterol regulatory element-binding protein (SREBP) family and similar proteins; The SREBP family includes SREBP1 and SREBP2, which are bHLHzip transcriptional activator of genes encoding proteins essential for cholesterol biosynthesis/uptake and fatty acid biosynthesis. SREBP1 and SREBP2 are principally found in the liver and in adipocytes and made up of an N-terminal transcription factor portion (composed of an activation domain, a bHLHzip domain, and a nuclear localization signal), a hydrophobic region containing two membrane spanning regions, and a C-terminal regulatory segment. They recognize a symmetric sterol regulatory element (TCACNCCAC) instead of E-box. The family also includes Saccharomyces cerevisiae transcription factor HMS1 (also termed high-copy MEP suppressor protein 1) and serine-rich protein TYE7. HMS1 is a putative bHLHzip transcription factor involved in exit from mitosis and pseudohyphal differentiation. TYE7, also termed basic-helix-loop-helix protein SGC1, is a putative bHLHzip transcription activator required for Ty1-mediated glycolytic gene expression. TYE7 N-terminal is extremely rich in serine residues. It binds DNA on E-box motifs, 5'-CANNTG-3'. TYE7 is not essential for growth.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 326205341  54 QGLNTAFDRLRRVVPQWGQDK---------------KLSKYETLQMALSYIMALTRILAEAER 101
Cdd:cd11395   16 SNLNTKIERLRDAIPSLRSPEgksddgglgglapttKLSKATILTKAIEYIRHLEQENERLEE 78

basic helix-loop-helix (bHLH) domain found in oligodendrocyte transcription factor 3 (Oligo3) and similar proteins; Oligo3, also termed Class B basic helix-loop-helix protein 7 (bHLHb7), or Class E basic helix-loop-helix protein 20 (bHLHe20), is a bHLH transcription factor that 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 326205341  52 RMQGLNTAFDRLRRVVP--QWGQDKKLSKYETLQMALSYIMALTRILAEAERF 102
Cdd:cd18941   27 RMHDLNLAMDGLREVMPyaHGPSVRKLSKIATLLLARNYILMLTSSLEEMKRL 79

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
                 ....*....|....*....|....*....|....*....|....*....
gi 326205341  50 RRRMQGLNTAFDRLRRVVPQ--WGQDKKLSKYETLQMALSYIMALTRIL 96
Cdd:cd11425   10 RLRMRTLADALGELRQHLPPsvAPKGKRLSKIQTLKYAIRYIGYLGNVL 58

basic helix-loop-helix-orange (bHLH-O) domain found in hairy and enhancer of split (HES)-related repressor protein (HERP)-like family; The HERP-like family includes bHLH-O transcriptional regulators that are related to the Drosophila hairy and Enhancer-of-split proteins. They contain a basic helix-loop-helix (bHLH) domain with an invariant glycine residue in its basic region, an orange domain in the central region and YXXW sequence motif at its C-terminal region. HERP proteins (HEY1, HEY2 and HEYL) act as downstream effectors of Notch signaling. They are involved in cardiovascular development and have roles in somitogenesis, myogenesis and gliogenesis. Hairy and enhancer of split-related protein HELT is a transcriptional repressor expressed in the developing central nervous system. It binds preferentially to the canonical E box sequence 5'-CACGCG-3' and regulates neuronal differentiation and/or identity. Differentially expressed in chondrocytes proteins, DEC1 and DEC2, are widely expressed in both embryonic and adult tissues and have been implicated in apoptosis, cell proliferation, and circadian rhythms, as well as malignancy in various cancers. Drosophila melanogaster protein clockwork orange (Cwo) is also included in this family. It is involved in the regulation of Drosophila circadian rhythms. It functions as both an activator and a repressor of clock gene expression.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 326205341  56 LNTAFDRLRRVVP---QWGQDKKLSKYETLQMALSYIMALT 93
Cdd:cd11389   12 INESLAELRRLVPearKSKGSGKLEKAEILEMTLQHLKALQ 52

basic helix-loop-helix (bHLH) domain found in Drosophila melanogaster protein extra-macrochaetae and similar proteins; Extra-macrochaetae is a negative regulator of sensory organ development in Drosophila. It belongs to dominant negative group of helix-loop-helix (dnHLH) proteins, which lack a basic DNA-binding domain but can form heterodimers with other HLH proteins, thereby inhibiting DNA binding.

                         10        20        30
                 ....*....|....*....|....*....|...
gi 326205341  60 FDRLRRVVPQWGQDKKLSKYETLQMALSYIMAL 92
Cdd:cd19695   12 LAKLRNLVPTLPKNRKVSKLELLQHVIDYIADL 44