Sin mutations alter inherent nucleosome mobility.
Previous studies have identified sin mutations that alleviate the requirement for the yeast SWI/SNF chromatin remodelling complex, which include point changes in the yeast genes encoding core histones. Here we characterise the biochemical properties of nucleosomes bearing these mutations. We find that sin mutant nucleosomes have a high inherent thermal mobility. As the SWI/SNF complex can alter nucleosome positioning, the higher mobility of sin mutant nucleosomes provides a means by which sin mutations may substitute for SWI/SNF function. The location of sin mutations also provides a new opportunity for insights into the mechanism for nucleosome mobilisation. We find that both mutations altering histone DNA contacts at the nucleosome dyad and mutations in the dimer-tetramer interface influence nucleosome mobility. Furthermore, incorporation of H2A.Z into nucleosomes, which also alters dimer-tetramer interactions, affects nucleosome mobility. Thus, variation of histone sequence or subtype provides a means by which eukaryotes may regulate access to chromatin through alterations to nucleosome mobility.
Flaus
Andrew
A
Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK.
Rencurel
Chantal
C
Ferreira
Helder
H
Wiechens
Nicola
N
Owen-Hughes
Tom
T
D002122:Calcium Chloride / Q000494:pharmacology; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015636:Magnesium Chloride / Q000494:pharmacology; D008958:Models, Molecular; D009038:Motion; D009154:Mutation; D009707:Nucleosomes / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D013696:Temperature; D014157:Transcription Factors / Q000378:metabolism
D006657:Histones; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D015636:Magnesium Chloride; D004247:DNA; D002122:Calcium Chloride