Specific contributions of histone tails and their acetylation to the mechanical stability of nucleosomes.
The distinct contributions of histone tails and their acetylation to nucleosomal stability were examined by mechanical disruption of individual nucleosomes in a single chromatin fiber using an optical trap. Enzymatic removal of H2A/H2B tails primarily decreased the strength of histone-DNA interactions located approximately +/-36bp from the dyad axis of symmetry (off-dyad strong interactions), whereas removal of the H3/H4 tails played a greater role in regulating the total amount of DNA bound. Similarly, nucleosomes composed of histones acetylated to different degrees by the histone acetyltransferase p300 exhibited significant decreases in the off-dyad strong interactions and the total amount of DNA bound. Acetylation of H2A/H2B appears to play a particularly critical role in weakening the off-dyad strong interactions. Collectively, our results suggest that the destabilizing effects of tail acetylation may be due to elimination of specific key interactions in the nucleosome.
Brower-Toland
Brent
B
Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA.
Wacker
David A
DA
Fulbright
Robert M
RM
Lis
John T
JT
Kraus
W Lee
WL
Wang
Michelle D
MD
D000107:Acetylation; D000595:Amino Acid Sequence; D004247:DNA / Q000378:metabolism; D005786:Gene Expression Regulation; D006657:Histones / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013816:Thermodynamics; D014158:Transcription, Genetic / Q000235:genetics
D006657:Histones; D009707:Nucleosomes; D004247:DNA