The expression of the Drosophila segmentation gene fushi tarazu (ftz) is controlled at the level of transcription. The proximal enhancer, located approximately 3.4 kb upstream of the transcription start site, directs lacZ fusion gene expression in a ftz-like seven-stripe pattern in transgenic fly embryos. We have taken a biochemical approach to identify DNA-binding proteins that regulate ftz gene expression through the proximal enhancer. DNase I footprinting and methylation interference experiments with staged Drosophila embryo nuclear extracts identified nine protein binding sites in the proximal enhancer. Ten different sequence-specific DNA-binding complexes that interact with eight of these sites were identified. Some interact with multiple sites, while others bind to single sites in the enhancer. Two of the complexes that interact with multiple sites appear to contain the previously described ftz regulators, FTZ-F1 and TTK/FTZ-F2. These in vitro studies allowed us to narrow down the proximal enhancer to a 323-bp DNA fragment that contains all of the protein binding sites. Expression directed by this minimal enhancer element in seven ftz-like stripes in transgenic embryos is identical to that directed by the full-length enhancer. Internal deletions of several sites abolish reporter gene expression in vivo. Thus, the ftz proximal enhancer, like other cell-type-specific eukaryotic enhancers, interacts with an array of proteins that are expected to mediate the establishment, maintenance, and repression of transcription of the ftz gene in seven stripes in the developing embryo.
[1]
G. Lavorgna,et al.
FTZ-F1, a steroid hormone receptor-like protein implicated in the activation of fushi tarazu
,
1991,
Science.
[2]
A. Schier,et al.
Analysis of the ftz upstream element: germ layer-specific enhancers are independently autoregulated.
,
1990,
Genes & development.
[3]
C. S. Parker,et al.
Transcriptional regulation of the Drosophila segmentation gene fushi tarazu (ftz)
,
1990,
BioEssays : news and reviews in molecular, cellular and developmental biology.
[4]
M. Noll,et al.
Isolation of two tissue‐specific Drosophila paired box genes, Pox meso and Pox neuro.
,
1989,
The EMBO journal.
[5]
R. Tjian,et al.
Transcription factors that activate the Ultrabithorax promoter in developmentally staged extracts
,
1988,
Cell.
[6]
S. Carroll,et al.
Localization of the fushi tarazu protein during Drosophila embryogenesis
,
1985,
Cell.
[7]
C. Nüsslein-Volhard,et al.
Mutations affecting segment number and polarity in Drosophila
,
1980,
Nature.
[8]
L. Staudt,et al.
Immunoglobulin gene transcription.
,
1991,
Annual review of immunology.