Insulin gene enhancer binding protein Isl-1 is a member of a novel class of proteins containing both a homeo- and a Cys-His domain.
The activity of the rat insulin I gene enhancer is mainly dependent on two cis-acting protein-binding domains. Here we report the isolation of a complementary DNA encoding a protein, Isl-1, that binds to one of these domains. Isl-1 contains a homeodomain with greatest similarity to those of the Caenorhabditis elegans proteins encoded by mec-3 and lin-11. In addition, Isl-1, like the lin-11 and mec-3 gene products, contains a novel Cys-His domain which is reminiscent of known metal-binding regions. Together these proteins define a novel class of proteins containing both a homeo- and a Cys His-domain. Isl-1 is preferentially expressed in cells of pancreatic endocrine origin. If the structural homologies between Isl-1 and the C. elegans gene products reflect functional similarities, a role for Isl-1 in the development of pancreatic endocrine cells could be envisaged.
Department of Microbiology, University of Umeå, Sweden.
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O
Karlsson
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S
Thor
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T
Norberg
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H
Ohlsson
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T
Edlund
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002107:Caenorhabditis / Q000032:analysis; D003001:Cloning, Molecular; D003545:Cysteine; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000235:genetics; D005801:Genes, Homeobox; D006639:Histidine; D018398:Homeodomain Proteins; D007328:Insulin / Q000235:genetics*; D060850:LIM-Homeodomain Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins; D012313:RNA / Q000032:analysis; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D007328:Insulin; D060850:LIM-Homeodomain Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1; D006639:Histidine; D012313:RNA; D004247:DNA; D003545:Cysteine