Stimulation of transcription by an Ultrabithorax protein in vitro.
The Ultrabithorax (Ubx) gene of Drosophila melanogaster encodes a family of UBX proteins that are thought to specify the developmental fates of segments in the posterior thorax and anterior abdomen by controlling the expression of a set of target genes. UBX proteins bind DNA in vitro, and they activate or repress different natural and synthetic target promoters in cultured cells. Here it is shown that a purified UBX protein can stimulate transcription of a synthetic target gene in extracts of cultured D. melanogaster cells. Stimulation is dependent on the presence of upstream, promoter-region binding sites but is independent of binding site orientation. A naturally occurring binding site cluster and a binding site consensus sequence consisting of TAA trinucleotide repeats can mediate this activation. A minimal promoter fused to such sites is activated by UBX, suggesting that transcriptional stimulation could result from an interaction between the promoter-bound protein and the general transcriptional machinery.
Johnson
F B
FB
Department of Biochemistry, Stanford University, California 94305.
Krasnow
M A
MA
D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics*; D005786:Gene Expression Regulation; D005801:Genes, Homeobox; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D014157:Transcription Factors