Transcription of Djun from D. melanogaster is positively regulated by DTF-1, AP-1, and CREB binding sites.
Djun is the homolog of the mammalian proto-oncogene jun in D. melanogaster, where it encodes a component of an AP-1-like nuclear DNA binding protein, or transcription factor. Djun, unlike its vertebrate counterparts, contains an intron in its 5' noncoding region. The expression of Djun in cultured Schneider line 2 cells is controlled by multiple cis-acting elements in its promoter region and the 5' noncoding region of the transcription unit. A 43-bp 5' upstream promoter region is necessary for the transcription activity of Djun. Deletion of this fragment decreased transcriptional activity by 67-fold. This region includes a TATA box and a sequence similar to the Drosophila transcription factor 1 (DTF-1) consensus sequence (GCAACAT/GC/C). A large DNase I footprint covering both the DTF-1 binding site and the TATA box was detected in this region when incubated with nuclear extract from Drosophila embryos, suggesting interactions with related transcription factors. This 43-bp sequence alone, containing the DTF-1 binding site and TATA box, however, is not sufficient for transcription activity. An 80-bp sequence including the start of transcription has considerable basal activity. An intragenic region containing an AP-1 site and a CRE site modulates or fine tunes activity of the promoter. Its activity as an enhancer is reduced when moved upstream in either orientation. An extragenic region containing two AP-1 sites similarly affects promoter activity.
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Zoology Department, Arizona State University, Tempe 85287-1501.
Goldstein
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D000818:Animals; D001483:Base Sequence; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005786:Gene Expression Regulation; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; C058437:DTF-1 protein, Drosophila; D029721:Drosophila Proteins; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D004247:DNA