Genome-wide maps of histone modifications in the SV40 virus

In order to better understand the nature of the changes in chromatin structure which occur during encapsidation, we have analyzed SV40 virions and minichromosomes for the organization of nucleosomes carrying specific histone tail modifications and RNA Polymerase II (RNAPII) and report here evidence that encapsidation leads to a reorganization of chromatin structure within the regulatory region of the virus and relief of the repression of early transcription. Examination of ChIP-seq profiles of the histone modifications H3K4me1, H3K4me2, H3K4me3, H3K9me1, H3K9me2, H3K9me3, H3K20me1, H4K20me1, HH4, HH3, and RNA polymerase, in wild-type (776) SV40 mini-chromosomes and virions.