Isolation of Drosophila CREB-B: a novel CRE-binding protein.
CREB is a DNA-binding protein that stimulates gene transcription upon activation of the cAMP signaling pathway. The mammalian CREB protein consists of an amino-terminal transcriptional activation domain and a carboxy-terminal DNA-binding domain comprised of a basic region and a leucine zipper. Recent studies have shown that the mammalian CREB is one of many transcription factors that can bind to the cAMP regulated enhancer (CRE) sequence. Consequently, a complete understanding of regulation through the CRE sequence requires the elucidation of how the various CRE-binding proteins interact with each other. To accomplish this goal, we have begun to characterize the family of CRE-binding proteins in a system that is amenable to genetic manipulations, Drosophila melanogaster. We have previously cloned a protein designated dCREB-A from a Drosophila embryonic cDNA library. Here, we describe an additional member of the Drosophila CREB gene family, isolated by screening a lambda gt11 library of adult Drosophila head cDNAs with a multimerized CRE sequence. This protein, dCREB-B, contains 285 amino acids and is remarkably similar within the basic/zipper region to the corresponding portion of mammalian CREB. In contrast, the dCREB-B and mammalian CREB zipper domains differ considerably from the dCREB-A zipper in both length and composition. However, the putative DNA binding domains for all three proteins are highly conserved. The activator region of dCREB-B is completely different from that of both mammalian CREB and dCREB-A. Northern blot analysis shows that multiple transcripts of the dCREB-B gene are expressed in embryonic and adult tissues and that these transcripts arise from both strands of the DNA.(ABSTRACT TRUNCATED AT 250 WORDS)
Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201.
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Usui
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Smolik
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RH
Goodman
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000302:isolation & purification*; D004330:Drosophila / Q000378:metabolism*; D017344:Genes, Insect; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D017362:Cyclic AMP Response Element-Binding Protein