Studies on the Chemical Nutagen-induced DNA Repair Synthesis in Relation to Chromosome Exchanges

突然變異誘發原에 의한 DNA回復合成과 染色體交換과의 聯關性에 관한 硏究

DNA repari synthesis and chromosome aberrations induced by various concentrations of alkylating agents (MMS, MNNG, MMC) in cultured human lymphocytes and HeLa $S_3$ cells were studied to determine the possibility of correlation between these two types of biological phenomena, and the results obtained were as follows: DNA repair synthesis was detected in MMC, MNNG and MMS treated HeLa $S_3$ cells at the concentrations of $3 \\times 10^{-7}M, 1 \\times 10^{-6}M, 5 \\times 10^{-4}M$, respectively. These results indicate that MMC is the most potent mutagen followed by MNNG, and MMS is the least potent among these three types of alkylating agents. MMC and MNNG did not show any significant increases of DNA repair synthesis as dose increased, while MMS did. Chromosome aberrations induced by MMC in human lymphocytes was increased as dose increased, but not chromosome exchanges. MNNG did not induce any significant amount of chromosome aberrations with doses, and exchanges were not observed in MNNG treated cells. MMS, however, induced both chromosome aberrations and exchanges, and their rates were increased as dose increased. These results suggest that DNA repair synthesis induced by these alklating agents may not be directly related to the production of chromosome aberrations and exchanges.

DNA 回復合成과 染色體交換과의 聯關性을 추구하기 위해 알킬화제 突然變異誘發原인 MMC, MNNG, MMS를 培養한 사람의 淋巴球와 HeLa $S_3$ 細胞에 處理하여 다음과 같은 結果를 얻었다. 1. 이들 알킬화제에 의해 誘發된 DNA 回復合成은 MMC, MNNG, MMS의 濃度가 각각 $3 \\times 10^-7, 1 \\times 10^-6, 5 \\times 10^-4 M$에서 檢出되었다. 이는 MMC가 가장 强力한 DNA 回復合成 誘發原이며 다음이 MNNG 그 다음이 MMS임을 뜻한다. MMC와 MNNG는 濃度增加에 따른 DNA 回復合成에 큰 차이를 보이지 않으나 MMS는 현저한 增加를 보인다. 2. MMC에 의한 染色體異常은 濃度가 增加함에 따라 그 率에 현저한 增加를 보이나 染色體交換率에는 별차이가 없다. 그러나 MNNG는 染色體異常率에 차가 없고 染色體交換은 觀察되지 않았다. MMS는 染色體異常 및 染色體交換 모두 濃度의 增加에 따른 그 率의 增加를 나타낸다. 이러한 結果는 突然變異誘發原에 의한 DNA 回復合成이 染色體交換 및 染色體異常과 직접적인 연관성이 없음을 시사하는 것이다.