Functional requirements for Fab-7 boundary activity in the bithorax complex

Daniel Wolle, Fabienne Cleard, Tsutomu Aoki, Girish Deshpande, Paul Schedl, Francois Karch

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Chromatin boundaries are architectural elements that determine the three-dimensional folding of the chromatin fiber and organize the chromosome into independent units of genetic activity. The Fab-7 boundary from the Drosophila bithorax complex (BX-C) is required for the parasegment-specific expression of the Abd-B gene. We have used a replacement strategy to identify sequences that are necessary and sufficient for Fab-7 boundary function in the BX-C. Fab-7 boundary activity is known to depend on factors that are stage specific, and we describe a novel ~700-kDa complex, the late boundary complex (LBC), that binds to Fab-7 sequences that have insulator functions in late embryos and adults. We show that the LBC is enriched in nuclear extracts from late, but not early, embryos and that it contains three insulator proteins, GAF, Mod(mdg4), and E(y)2. Its DNA binding properties are unusual in that it requires a minimal sequence of >65 bp; however, other than a GAGA motif, the three Fab-7 LBC recognition elements display few sequence similarities. Finally, we show that mutations which abrogate LBC binding in vitro inactivate the Fab-7 boundary in the BX-C.

Original languageEnglish (US)
Pages (from-to)3739-3752
Number of pages14
JournalMolecular and cellular biology
Volume35
Issue number21
DOIs
StatePublished - 2015

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Functional requirements for Fab-7 boundary activity in the bithorax complex'. Together they form a unique fingerprint.

  • Cite this