BioProject

Chromatin insulators are DNA protein complexes that mediate inter and intra chromosomal interactions. More...

Chromatin insulators are DNA protein complexes that mediate inter and intra chromosomal interactions. Boundary Element Associated Factor- 32 (BEAF-32) is an insulator protein predominantly found near gene promoters and thought to play a role in gene expression. We find that mutations in BEAF-32 are lethal, show loss of epithelial morphology in imaginal discs and cause neoplastic growth defects. To investigate the molecular mechanisms underlying this phenotype, we carried out a genome-wide analysis of BEAF-32 localization in wing imaginal disc cells. Mutation of BEAF-32 results in miss-regulation of 3850 genes by at least 1.5-fold, 647 of which are bound by this protein in wing imaginal cells. Up-regulated genes encode proteins such as Bazooka, a determinant of cell polarity; the Insulin receptor-1 and the p70-S6 kinase, involved in the insulin growth factor pathway that can activate various pathways involved in cell proliferation; and the Unpaired 3 ligand of the Janus kinase (JNK) pathway, and its target gene Socs35, which can also activate cell proliferation. The expression of genes involved in DNA homologous end repair and oxidative stress pathways is also increased in BEAF-32 mutants. Among the down-regulated genes are those encoding components of the Wingless pathway, which is required for cell differentiation, and amino acid metabolism. Miss-regulation of these genes explains the unregulated cell growth and neoplastic phenotypes observed in imaginal tissues of BEAF-32 mutants. Overall design: Here we examine mapping the genomic binding sites and its distribution of BEAF-32, a Drosophila insulator proteins in wing imaginal tissue. We performed ChIP-seq analysis using BEAF-32B. Less...