Thymine dimer formation as a probe of the path of DNA in and between nucleosomes in intact chromatin.
Photo-induced thymine dimer formation was used to probe nucleosome structure in nuclei. The distribution of thymine dimers in the nucleosome and recent studies of the structure of thymine dimer-containing DNA suggest that the rate of thymine dimer formation is affected by the direction and degree of DNA bending. This premise was used to construct a model of the path of DNA in the nucleosome, which has the following features. (i) There are four regions of sharp bending, two which have been seen previously by x-ray crystallography of the core particle. (ii) The DNA in H1-containing nucleosomes deviates from its superhelical path near the midpoint; this is not seen with H1-stripped chromatin. (iii) The internucleosomal (linker) DNA appears to be relatively straight.
Pehrson
J R
JR
Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111.
D000818:Animals; D001548:Benzalkonium Compounds / Q000138:chemical synthesis / Q000494:pharmacology; D002843:Chromatin / Q000528:radiation effects*; D004247:DNA / Q000187:drug effects / Q000528:radiation effects*; D006657:Histones / Q000302:isolation & purification; D008099:Liver / Q000378:metabolism; D008961:Models, Structural; D009707:Nucleosomes / Q000528:radiation effects*; D011740:Pyrimidine Dimers / Q000032:analysis*; D051381:Rats
D001548:Benzalkonium Compounds; D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D011740:Pyrimidine Dimers; C062015:N-(3-acetylbenzyl)-N,N-dimethylethylenediammonium dichloride; D004247:DNA