Nucleosome structure directly influences gene transcription. However, the function of each histone residue remains largely unknown. Here we profiled gene expression changes upon the mutation of individual residues of histone H3 and H4. Histone residues grouped by expression change similarity displayed overall structural relevance. This regulatory functional map of the core histones led to novel findings. First, the residues specific to each histone family tend to be more influential than those commonly found among different histones. Second, unlike histone acetylations, H3K4 trimethylation does not appear to be prerequisite for gene activation. Third, H3Q5 has been newly identified for its putative interactions with many chromatin regulators for transcription control. Lastly, the nucleosome lateral surface seems to play a key role through interactions with the surrounding DNA. Remarkably, we discovered a novel role for H3K56 in chromatin dynamics. The deletion of this residue, but not the alteration of acetylation states, caused a genome-wide decrease in nucleosome mobility and stabilized nucleosome positioning near transcription start and end sites. Occupying the DNA entry/exit site, H3K56 is thought to modulate nucleosome sliding along DNA. Taken together, genomics approaches such as microarray and deep sequencing prove valuable for mapping the function of histone residues. SUBMITTER_CITATION: Global Mapping of the Regulatory Interactions of Histone Residues, Epigenomics Keystone Symposium, January 21th (2012).
Overall design
Microarray analysis was performed for 123 histone mutants and four wild-types as two reaplications of H3 and H4 of Saccharomyces ceravisiae.
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