Benzo(a)pyrene Diolepoxide를 처리한 쥐 육종세포내의 DNA Polymerase α and β의 활성도의 변화

Abstract

Enzyme activities of DNA polymerase α and β have been analyzed in anti (+)-r-7, t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) treated mouse sarcoma cells. The time courses of repair synthesis following treatment of mouse sarcoma cells with 400 ng/ml of BPDE as measured by ³H-thymidine incorporation into the cells for 1 hr show biphasic curve, which indicates two apparent repair phases. Two distinct chromatographic elution profiles of DNA polymerases were observed when cells were treated with carcinogen and post incubated for 3 or 9 hrs, and cell homogenates were applied onto DEAE-52 anion exchange column. Cellular level of DNA polymerase α activity allowed to repair the DNA damage for 3 hrs was significantly higher than that of DNA polymerase β while DNA polymerase β activity was a predominant one in 9 hrs post incubated cells. Data presented here suggest that both DNA polymerase α and β are required to resynthesize the excised DNA damage, and that DNA polymerase α is the major enzyme involved in the resynthesis of DNA damage after endonuclease nicking step while DNA polymerase β is playing the major role in filling the rest of the gap thereafter.