Nucleosome rotational setting is associated with transcriptional regulation in promoters of tissue-specific human genes
Dyogen Group, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), 46 rue d'Ulm, CNRS UMR8197, INSERM U1024, 75005 Paris Cedex 05, France
Genome Biology 2010, 11:R51 doi:10.1186/gb-2010-11-5-r51Published: 12 May 2010
The position of a nucleosome, both translational along the DNA molecule and rotational between the histone core and the DNA, is controlled by many factors, including the regular occurrence of specific dinucleotides with a period of approximately 10 bp, important for the rotational setting of the DNA around the histone octamer.
We show that such a 10 bp periodic signal of purine-purine dinucleotides occurs in phase with the transcription start site (TSS) of human genes and is centered on the position of the first (+1) nucleosome downstream of the TSS. These data support a direct link between transcription and the rotational setting of the nucleosome. The periodic signal is most prevalent in genes that contain CpG islands that are expressed at low levels in a tissue-specific manner and are involved in the control of transcription.
These results, together with several lines of evidence from the recent literature, support a new model whereby the +1 nucleosome could be more efficiently disassembled from gene promoters by H3K56 acetylation marks if the periodic signal specifies an optimal rotational setting.