The Drosophila Fos-related AP-1 protein is a developmentally regulated transcription factor.
Drosophila AP-1 consists of two proteins (dFRA and dJRA) that have functional and structural properties in common with mammalian Fos and Jun proto-oncogene products. Here, we report the isolation and characterization of cDNAs encoding the full-length dFRA and dJRA proteins. The predicted amino acid sequences reveal that both proteins contain a bipartite DNA-binding domain consisting of a leucine repeat and an adjacent basic region, which are characteristic of members of the AP-1 family. By using protein translated in vitro or expressed in Escherichia coli, we demonstrate that dFRA, in contrast to the mammalian cFos proteins, recognizes the AP-1 site on its own and activates transcription in vitro in the absence of dJRA or Jun. Heteromeric complexes formed between dFRA and dJRA bind the AP-1 site better than either protein alone, and the two proteins activate transcription synergistically in vitro. In the developing embryo, dFRA mRNA is first expressed in a limited set of cells in the head and is later restricted to a subset of peripheral neurons, several epidermal cells near the muscle attachment sites, and a portion of the gut. In contrast, dJRA appears to be uniformly expressed at a low level in all cell types. These results indicate that dFRA is a developmentally regulated transcription factor and suggest that its potential interplay with dJRA plays an important role in cell-type-specific transcription during Drosophila embryonic development.
Perkins
K K
KK
Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Admon
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A
Patel
N
N
Tjian
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D004247:DNA