Staged embryos designated for ChIP-seq analysis were cross-linked with a 2% formadehyde solution (diluted in 500 mL M9 buffer) for 30 minutes, followed by the addition of 125 mM glycine to quench the reaction, and two final washes in PBS + protease inhibitors. Extracts were prepared from synchronized egl-30(tg26) embryos by standard methods described previously (Reichsteiner et al. 2010, Ercan et al. 2007). Approximately 2 mg of extract from each embryo stage was immunoprecipitated with 2 ug of commercially available antibodies previously cited in C. elegans chromatin studies Extracted DNA was prepared into ChIP-seq libraries using the NEBNext Ultra DNA library preparation kit for Illumina (New England Biolabs) and was sequenced on the HiSeq 2500 platform