High- resolution profiling of histone methylations in the human genome

Here authors reported another ChIPSeq implementation (see Johnson DS. et al., and Mikkelsen TS. et al. for related posts), and used it to map histone modifications in human CD4+ T cells.

The flow chart of ChIPSeq (Barski A. et al./Cell)

To distinguish between this procedure [ChIP combined with Solexa sequencing] and our previous procedure, GMAT, or other similar procedures that incorporate the SAGE protocol, we have termed this direct sequencing procedure 'ChIP-Seq'. [...] Our data indicate that H3K27me1 and H4K20me1 are associated with actively transcribed regions. Moreover, H3K9me1 and H2BK5me1 are also associated with transcribed regions. [...] However, our data suggest that H3K79me1 is modestly associated with activation while H3K79me3 is associated with repression in human cells. H3K79me2 did not show any preference toward either active or silent genes. Therefore, actively transcribed regions are marked with high levels of H3K36me3, H3K27me1, H3K9me1, and H2BK5me1. H3K36me3 exhibits a more 3' distribution, whereas H3K9me1 and H2BK5me1 exhibit higher levels near the 5' end, and H3K27me1 distribute more evenly throughout the transcribed regions.

Barski A. et al. 2007. Cell 129:823-837

epigenetics