In vivo binding of su(Hw) in the Drosophila genome

ABSTRACT: There is considerable evidence that insulator elements are likely to play a key role in the organisation of the regulatory architecture of the genome. In Drosophila, one of the best studied insulator elements is the gypsy insulator in the gypsy retrotransposon whose function is dependent on the Su(Hw) Zn-finger DNA binding protein. Although there are several hundred Su(Hw) sites in the genome which are proposed to act as endogenous insulator elements, analysis of the role of the Su(Hw) protein has focussed on the gypsy insulator and few endogenous sites have yet been identified. We have used chromatin immunopurification coupled to genomic microarray analysis to identify Su(Hw) binding sites within a representative region of the Drosophila genome; the 3MB Adh region on chromosome 2L. We have located about 60 Su(Hw) binding sites across this region and this has enabled us to construct a robust new Su(Hw) binding site consensus based on these in vivo sites. In contrast to the gypsy insulator which contains 12 Su(Hw) binding sites within 340bp, the endogenous sites are not present in clusters. We identify two key features of these endogenous Su(Hw) sites. Firstly, in contrast to most analyses of DNA binding protein specificity, we find that strong matches to the binding consensus are good predictors of binding site occupancy. Secondly, examination of Su(Hw) binding site occupancy in 0-20hr embryos, 3rd larval instar brains or 3rd larval imaginal discs reveals a constant pattern of Su(Hw) binding indicating that most , if not all Su(Hw) sites are constitutively occupied. These two features support a constant genomic architectural role for the Su(Hw) protein. Keywords: ChIP-chip

ORGANISM(S): Drosophila melanogaster

PROVIDER: GSE4691 | GEO | 2006/06/20

SECONDARY ACCESSION(S): PRJNA96735

REPOSITORIES: GEO