体外SV40染色质中嘧啶二聚体形成的效率。

Efficiency of formation of pyrimidine dimers in SV40 chromatin in vitro.

作者信息

Snapka R M, Linn S

出版信息

Biochemistry. 1981 Jan 6;20(1):68-72. doi: 10.1021/bi00504a012.

Abstract

The efficiency of formation of pyrimidine dimers by 254-nm light was studied in mixtures of SV40 chromatin and DNA extracted from that chromatin. At high doses (beyond 380 J/m2), fewer dimers are formed in chromatin than in DNA for a given dose of radiation. This difference is about 10% as saturation with pyrimidine dimers is approached at 6840 J/m2. Conversely, at biologically repairable doses (up to 40 J/m2, less than 2 dimers/genome), significantly more dimers are produced in the chromatin than in the DNA. A maximum increase of about 50% occurs at doses producing 0.5--20 dimers/genome. With isolated nucleosomes from this chromatin, a maximum increase in dimer formation of 77% was observed. Therefore, the increased dimer formation in the whole chromatin can be wholly accounted for in the nucleosome portion.

摘要

在SV40染色质与从该染色质中提取的DNA的混合物中，研究了254纳米光形成嘧啶二聚体的效率。在高剂量（超过380 J/m²）下，对于给定剂量的辐射，染色质中形成的二聚体比DNA中少。当在6840 J/m²接近嘧啶二聚体饱和时，这种差异约为10%。相反，在生物可修复剂量（高达40 J/m²，每基因组少于2个二聚体）下，染色质中产生的二聚体明显多于DNA。在产生0.5-20个二聚体/基因组的剂量下，最大增加约50%。用来自该染色质的分离核小体，观察到二聚体形成的最大增加为77%。因此，整个染色质中二聚体形成的增加可以完全由核小体部分来解释。