Chromatin marks and RNA Pol II in human hematopoietic stem and progenitor cells

The transcriptional status of genes can be determined from the enrichment pattern of RNA polymerase at the transcription start site (TSS) and across the body of the gene. Active elongating genes are enriched for H3K79me2, and Polycomb paused genes are marked by H3K27me3. Human CD133-positive Umbilical Cord Blood (UCB) cells were cross-linked with formaldehyde for 20 min. DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing. A sample of whole cell extract (WCE) was sequenced and used as the background to determine enrichment. ChIP was performed using an antibody against total RNA Pol2 (Covance 8WG16), H3K27me3 (Abcam ab6002) and H3K79me2 (Abcam ab3594).