The enhancer-blocking activity of the Fab-7 boundary from the Drosophila bithorax complex requires GAGA-factor-binding sites.
In the work reported here we have analyzed the role of the GAGA factor [encoded by the Trithorax-like (Trl) gene] in the enhancer-blocking activity of Frontabdominal-7 (Fab-7), a domain boundary element from the Drosophila melanogaster bithorax complex (BX-C). One of the three nuclease hypersensitive sites in the Fab-7 boundary, HS1, contains multiple consensus-binding sequences for the GAGA factor, a protein known to be involved in the formation and/or maintenance of nucleosome-free regions of chromatin. GAGA protein has been shown to localize to the Fab-7 boundary in vivo, and we show that it recognizes sequences from HS1 in vitro. Using two different transgene assays we demonstrate that GAGA-factor-binding sites are necessary but not sufficient for full Fab-7 enhancer-blocking activity. We show that distinct GAGA sites are required for different enhancer-blocking activities at different stages of development. We also show that the enhancer-blocking activity of the endogenous Fab-7 boundary is sensitive to mutations in the gene encoding the GAGA factor Trithorax-like.
Schweinsberg
Susan
S
Department of Molecular Biology, Princeton University, Princeton, New Jersey 08540, USA.
Hagstrom
Kirsten
K
Gohl
Daryl
D
Schedl
Paul
P
Kumar
Ram P
RP
Mishra
Rakesh
R
Karch
Francois
F
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D014157:Transcription Factors; C063460:Trl protein, Drosophila