High-Resolution ChIP-MNase Mapping of Nucleosome Positions at Selected Genomic Loci and Alleles.

The positioning of nucleosomes regulates the accessibility of genomic DNA and can impact the activities of functional elements. Nucleosome positioning is highly consistent at each genomic location in any particular cell-type, but can vary in an orchestrated fashion between different cell-types and between genomic loci according to their activities. Here, we describe a technique-"ChIP-MNase" (chromatin immunoprecipitation linked to micrococcal nuclease mapping)-to determine nucleosome positions at chosen sets of genomic features that can be defined by their molecular composition and recovered by chromatin immunoprecipitation.

Role of cell-type specific nucleosome positioning in inducible activation of mammalian promoters.

The organization of nucleosomes across functional genomic elements represents a critical layer of control. Here, we present a strategy for high-resolution nucleosome profiling at selected genomic features, and use this to analyse dynamic nucleosome positioning at inducible and cell-type-specific mammalian promoters. We find that nucleosome patterning at inducible promoters frequently resembles that at active promoters, even before stimulus-driven activation.

Zbtb7a is a transducer for the control of promoter accessibility by NF-kappa B and multiple other transcription factors.

Gene expression in eukaryotes is controlled by DNA sequences at promoter and enhancer regions, whose accessibility for binding by regulatory proteins dictates their specific patterns of activity. Here, we identify the protein Zbtb7a as a factor required for inducible changes in accessibility driven by transcription factors (TFs). We show that Zbtb7a binds to a significant fraction of genomic promoters and enhancers, encompassing many target genes of nuclear factor kappa B (NFκB) p65 and a variety of other TFs.