Concentration dependent chromatin states induced by the bicoid morphogen gradient.

TitleConcentration dependent chromatin states induced by the bicoid morphogen gradient.
Publication TypeJournal Article
Year of Publication2017
AuthorsHannon, CE, Blythe, SA, Wieschaus, EF
JournalElife
Volume6
Date Published2017 Sep 11
ISSN2050-084X
Abstract

In Drosophila, graded expression of the maternal transcription factor Bicoid (Bcd) provides positional information to activate target genes at different positions along the anterior-posterior axis. We have measured the genome-wide binding profile of Bcd using ChIP-seq in embryos expressing single, uniform levels of Bcd protein, and grouped Bcd-bound targets into four classes based on occupancy at different concentrations. By measuring the biochemical affinity of target enhancers in these classes in vitro and genome-wide chromatin accessibility by ATAC-seq, we found that the occupancy of target sequences by Bcd is not primarily determined by Bcd binding sites, but by chromatin context. Bcd drives an open chromatin state at a subset of its targets. Our data support a model where Bcd influences chromatin structure to gain access to concentration-sensitive targets at high concentrations, while concentration-insensitive targets are found in more accessible chromatin and are bound at low concentrations. This may be a common property of developmental transcription factors that must gain early access to their target enhancers while the chromatin state of the genome is being remodeled during large-scale transitions in the gene regulatory landscape.

DOI10.7554/eLife.28275
Alternate JournalElife
PubMed ID28891464
PubMed Central IDPMC5624782
Grant ListF31 HD082940 / HD / NICHD NIH HHS / United States
F32 HD072653 / HD / NICHD NIH HHS / United States