Zea mays Epigenomics

In this study we investigated the developmental dynamics of genes targeted in vivo by the transcription factor RAMOSA1, a key regulator of determinacy, and revealed potential mechanisms for repressing branches in distinct stem cell populations in developing maize inflorescences. To identify targets of RA1 and to distinguish direct vs. indirect interactions, we performed Chromatin Immunoprecipitation (ChIP)-seq and compared the results to gene expression data (RNA-seq datasets for Eveland et al., 2013, submitted). We mapped genome-wide occupancy of RA1 and showed that it differently regulates modules of target genes based on spatiotemporal context. Overall design: Plants expressing complementing RA1 transgenes tagged with HA or YFP were used in parallel experiments. Ear and tassel primordia were collected and tag-specific antibodies were used to pull down RA1 bound to its target loci. Genome-wide analysis of RA1 occupancy revealed thousands of putative binding sites (i.e. peaks significantly enriched (p < 1e-05) compared to input DNA).