Widlak P, Bykov V J, Hemminki K, Rzeszowska-Wolny J
Department of Tumor Biology, Institute of Oncology, Gliwice, Poland.
Cancer Lett. 1996 Nov 29;108(2):215-23. doi: 10.1016/s0304-3835(96)04426-6.
The formation of UV-induced photoproducts in the chromatin fractions of human lymphocytes was studied by 32P-post-labeling. A higher level of DNA lesions was found in the matrix-attached DNA fraction as compared to non-matrix DNA of irradiated cells (about 150 and 110 adducts per 10(6) nucleotides, respectively, at a 500 J/m2 254 nm-UV dose). Formation of photoproducts in a MAR (matrix attached region) sequence from the mouse kappa immunoglobulin gene irradiated in vitro was examined as well. The MAR sequence showed a two-fold higher level of adducts as compared to non-MAR DNA. The effect of photoproducts on complex-formation between MAR DNA and proteins of the nuclear matrix was studied in vitro. The amount of UV-induced adducts was 1.5-fold higher in matrix-bound fraction as compared to non-fractionated DNA (and five-fold higher as compared to unbound fraction), which possibly resulted from preferential binding of lesion-containing DNA fragments to the nuclear matrix proteins.
采用³²P后标记法研究了紫外线诱导的人类淋巴细胞染色质组分中光产物的形成。与受照射细胞的非基质DNA相比，在基质附着DNA组分中发现了更高水平的DNA损伤（在500 J/m² 254 nm紫外线剂量下，每10⁶个核苷酸分别约有150个和110个加合物）。还检测了体外照射的小鼠κ免疫球蛋白基因MAR（基质附着区域）序列中光产物的形成。与非MAR DNA相比，MAR序列的加合物水平高出两倍。在体外研究了光产物对MAR DNA与核基质蛋白之间复合物形成的影响。与未分级的DNA相比，基质结合组分中紫外线诱导的加合物量高1.5倍（与未结合组分相比高5倍），这可能是由于含损伤的DNA片段优先与核基质蛋白结合所致。
