Sequence-specific DNA-binding activities of the gap proteins encoded by hunchback and Krüppel in Drosophila.
The segmentation of the Drosophila body plan depends on a hierarchy of interactions among approximately 20-25 regulatory genes that are active in the early embryo (refs 1-4; for a review see ref. 5). The gap genes have a key role in this process and are responsible for the periodic expression of certain pair-rule genes and the localized expression of several homoeotic genes. The two best characterized gap genes, hunchback (hb) and Krüppel (Kr), contain homologies with the zinc-finger DNA-binding motif, although their mode of action in the early embryo is unknown. Here we report that both of the proteins encoded by these genes possess sequence-specific DNA-binding activities, which indicates that they might regulate gene expression at the level of transcription. The binding sites of the hb gene product are related by a 10-base pair (bp) consensus sequence, G/A C/C ATAAAAAA, whereas the binding sites of the Kr gene product share a distinct 10-bp motif, AACGGGTTAA. It is possible that the hb and Kr proteins cooperatively regulate gene expression, because they are expressed in broad, overlapping gradients in the early embryo. We also provide evidence that the on/off periodicity of the pair-rule gene even-skipped (eve) involves the interaction of the hb and Kr proteins with defined eve promoter elements.
Stanojević
D
D
Department of Biological Sciences, Fairchild Center, Columbia University, New York, New York 10027.
Hoey
T
T
Levine
M
M
D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D015870:Gene Expression; D007605:Juvenile Hormones; D051741:Kruppel-Like Transcription Factors; D008667:Metalloproteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors; D015032:Zinc / Q000378:metabolism
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D007605:Juvenile Hormones; C497244:Kr protein, Drosophila; D051741:Kruppel-Like Transcription Factors; D008667:Metalloproteins; D012097:Repressor Proteins; D014157:Transcription Factors; C061245:hb protein, Drosophila; D004247:DNA; D015032:Zinc