Hara R, Mo J, Sancar A
Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.
Mol Cell Biol. 2000 Dec;20(24):9173-81. doi: 10.1128/MCB.20.24.9173-9181.2000.
To investigate the effect of nucleosomes on nucleotide excision repair in humans, we prepared a mononucleosome containing a (6-4) photoproduct in the nucleosome core and examined its repair with the reconstituted human excision nuclease system and with cell extracts. Nucleosomal DNA is repaired at a rate of about 10% of that for naked DNA in both systems. These results are in agreement with in vivo data showing a considerably slower rate of repair of overall genomic DNA relative to that for transcriptionally active DNA. Furthermore, our results indicate that the first-order packing of DNA in nucleosomes is a primary determinant of slow repair of DNA in chromatin.
为了研究核小体对人类核苷酸切除修复的影响，我们制备了一种在核小体核心含有（6-4）光产物的单核小体，并使用重组的人类切除核酸酶系统和细胞提取物检测其修复情况。在这两种系统中，核小体DNA的修复速率约为裸DNA的10%。这些结果与体内数据一致，体内数据显示，相对于转录活性DNA，整体基因组DNA的修复速率要慢得多。此外，我们的结果表明，核小体中DNA的一级包装是染色质中DNA修复缓慢的主要决定因素。
