Identification of Myc and Max genomic targets in mouse embryonic stem cells.
Myc is a master transcription factor that has been demonstrated to be required for embryonic stem cell (ESC) pluripotency, self-renewal, and inhibition of differentiation. Although recent works identified several Myc-targets in ESC the list of Myc binding sites is largely incomplete due to the low sensitivity and specificity of the antibodies available so far. To systematically identify Myc binding sites in mouse ESCs here we used a stringent streptavidin based genome-wide chromatin immunoprecipitation (ChIP-Seq) of a biotin-tagged Myc (Bio-Myc) as well as a ChIP-Seq of the Myc partner Max. This analysis identified 4273 Myc binding sites of which more than 85%  co-occupied by Max, overlap with H3K4me3 positive promoters and active enhancers of transcriptional regulators, chromatin modifiers, and genes involved in stem cell self-renewing. The new sites identified were validated experimentally. This study provides a new Myc and Max binding reference in mouse ESCs. Overall design: ChIP-seq of bio-Myc and Max in E14 and respective controls; Bio-Myc ChIP-seq was performed in a stable clone of E14 mouse embryonic stem cell expressing Biotin-tagged Myc; Mock, Max and IgG were performed in parental wt E14 mESC.