Nucleosomes are context-specific, H2A.Z modulated barriers to RNA polymerase. Drosophila melanogaster

Nucleosomes are barriers to transcription in vitro, however, their effects on RNA polymerase in vivo are unknown. Here we describe a simple and general strategy to comprehensively map the positions of elongating and arrested RNA Polymerase II (RNAPII) at nucleotide resolution. Our results suggest that nucleosomes present significant, context-specific barriers to RNAPII in vivo that can be tuned by the incorporation of H2A.Z. Overall design: 8 sets of two replicates each of paired-end and 3 sets of two replicates each of single-end samples were sequenced and analyzed.