FIG. 4.

macroH2A1 nucleosomes are enriched on endogenous MLVs. The relative concentration of macroH2A1 was determined by real-time PCR using DNA from macroH2A1 nucleosomes that were purified by thiol-affinity chromatography (10). A value of 1 indicates a macroH2A1 concentration equal to that of the bulk chromatin applied to the thiol-affinity procedure. The values shown are the averages determined from four independent preparations. The P values for a t test of the enrichment were <0.02 at all sites (see Table S1 in the supplemental material for specific P values and the standard deviation analysis).