HIV-1 and MLV integration sites positions and nucleosome occupancy. 41 435 HIV-1 integration loci obtained from , and 32 631 MLV integration sites obtained from  were plotted to human genome and submitted to the nucleosome-positioning prediction analysis set up previously . The means of nucleosome occupancy surrounding the integration site (between −250 bp and 250 bp) are reported in (A). The means of nucleosome occupancy at the integration site are reported in (B) for MLV, HIV-1 and randomly generated insertion sites. The means of nucleosome occupancy in the region between −5 000 bp to + 5 000 bp from the integration site are reported in (C). Results are the means of the analyses performed from the 41435 HIV-1 and 32 361 MLV integrants. The means of nucleosomes occupancy in −1000 to 0, −500 to 0, 0 to 500 and 0 to 1000 bp regions surrounding the integration sites are reported in (D). Dotted lines represent the position of the integration sites and the global occupancy mean calculated for the entire genome.