An AP-1 binding site in the upstream region of Deb-A is part of a developmentally regulated negative element.
The Deb-A gene from Drosophila melanogaster encodes a small membrane-associated protein, regulated during development, with peak abundance at 12-15 h of embryogenesis. The cis-acting regulatory elements that control expression of Deb-A during embryogenesis were localized using a somatic transformation assay. The Adh gene of D. melanogaster was used as a 'reporter' gene. The promoterless ADH coding sequence was fused to the 5'-upstream control region of Deb-A. Deletions were introduced into the 5'-region using various restriction sites and Bal31 deletion mutagenesis. A negative regulatory element, or silencer, was localized to a segment 47 base pairs long, between -395 and -442. It is responsible for 80% of the repression of gene expression during late development and reduces levels of Deb-A RNA nearly 5-fold. This negative element is temporally functional. It becomes active after 15 h of embryogenesis and it has no effect on gene expression prior to that. Within this negative element of 47 base pairs, two footprint regions were protected from DNase I digestion by embryonic nuclear extracts: one region contains an AP-1 binding site, but the other footprint is due to unknown element(s). High molecular weight DNA-protein complexes on an oligonucleotide probe spanning the AP-1 binding site were identified in gel retardation assays using partially purified bacterially expressed Djun protein or nuclear extracts from Drosophila embryos. These data suggest that the AP-1 site may be partly responsible for decreasing Deb-A expression during the late embryonic developmental stages of D. melanogaster.
Wang
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Zoology Department, Arizona State University, Tempe 85287.
Goldstein
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D003850:Deoxyribonuclease I; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics*; D008969:Molecular Sequence Data; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics* / Q000378:metabolism
D016755:Proto-Oncogene Proteins c-jun; D003850:Deoxyribonuclease I