Replicational Errors Induced by Nucleoside Analogs in Cells

细胞中核苷类似物诱导的复制错误

• 批准号: 10044291
• 负责人: HAYATSU Hikoya
• 金额: $ 3.33万
• 依托单位: OKAYAMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044291/
• 关键词: Mismatch repair; Replicational errors; Retrovirus; MutS protein; Transition mutations; Error Catastrophe; mutL; Nucleoside analog; mut:L; error catastophe; P-ヌクレオシド; 突然変異; DNAポリメラーゼ; RNAポリメラーゼ; 転写エラー; 校正作用

Deoxyribosyl-dihydropyrimido[4,5-c] [1,2] oxazin-7-one (dP) is a potent mutagenic deoxycytidine analog capable of pairing with both A and G, thereby causing G-C to A-T and A-T to G-C transition mutations. We have found that the E. coli mismatch repair system can protect cells against this mutagenic action. dP is more mutagenic in mismatch-repair-defective mutH, mutL, and mutS strains than in a wild-type strain. At higher dP doses, the difference between the wild type and the mutator strains is smaller, suggesting that saturation of mismatch repair by dP may take place. Furthermore, introduction of a plasmid containing the mutLィイD1+ィエD1 gene into wile-type E. coli significantly reduced dP-induced mutagenesis. These results indicate that the mismatch repair system can remove replication errors induced by dP, but the capacity of this system to handle mismatches containing dP can be saturated. When cells were cultured at high dP concentration (20 μg/ml) final cell counts were reduced, and … More the frequency of RifィイD1rィエD1 mutants reached the high level of 10-ィイD14ィエD1. Colonies from those cultures were heterogeneously shaped, with 20-50% of them significantly smaller than control cells. We suggest that the cell killing and growth delay by dP are caused by excess mutations and saturation of mismatch repair (error catastrophe).We also found that P-ribonucleoside triphosphate (Rptp) is efficiently incorporated into RNA transcripts in place of either UTP and/or CTP. The incorporation of such ambiguous analog into transcripts might specifically induce random mutations in retroviruses such as HIV, but not in the host cell genome. To test this we analyzed mutagenic effects of in an in vitro system mimicking a life cycle of retroviruses. The results showed that Rptp randomly accumulated mutations in the RNA transcripts during each cycle, and after 4 cycles of replication the mutation frequency was raised to 3.8%. Over 90% of mutations induced during the cycles were found to be C-to-U or U-to-C as expected. Less

脱氧核糖基 - 二氢吡啶[4,5-C] [1,2]恶毒素-7-ONE（DP）是一种潜在的诱变脱氧胞苷的类似物，能够与A和G配对，从而导致G-C到A-T和A-T和A-T和A-T和A-T和G-C转移突变。我们发现大肠杆菌不匹配修复系统可以保护细胞免受这种诱变作用。与野生型菌株相比，DP在不匹配的修复缺陷，MUTL和MUTS菌株中更诱变。在较高的DP剂量下，野生型和突变器菌株之间的差异较小，这表明可能会通过DP进行不匹配修复的饱和。此外，引入含有Mutilli D1+IE D1基因的质粒中的大肠杆菌显着降低了DP诱导的诱变。这些结果表明，不匹配维修系统可以消除DP引起的复制误差，但是该系统处理包含DP的不匹配的能力可以饱和。在高DP浓度（20μg/ml）最终细胞计数下培养细胞，而……更多的RIFI D1RIE D1突变体的频率达到了10-II D14的高水平。这些培养物的菌落形状异质，其中20-50％明显小于对照细胞。我们建议DP的细胞杀死和生长延迟是由过量突变和不匹配修复的饱和（误差灾难）引起的。我们还发现，P三核苷三磷酸（RPTP）有效地将其纳入RNA转录本中，代替UTP和/或CTP。这种模棱两可的类似物的结合产业可能会在逆转录病毒（例如HIV）中特异性诱导随机突变，但在宿主细胞基因组中却没有。为了测试这一点，我们分析了模拟逆转录病毒生命周期的体外系统中的诱变作用。结果表明，RPTP在每个循环中随机积累的突变，在4个复制周期后，突变频率升高到3.8％。发现在周期期间诱导的突变中有超过90％的突变被预期为C-TO-U或U-TO-C。较少的

项目成果

K. Moriyama, Y. Kikkawa, D. Loakes and K. Negishi: "Disturbance of genetic information by a ribonucleotide analogue"Nucleic Acids Symposium Series. No.42. 131-132 (1999)

K. Moriyama、Y. Kikkawa、D. Loakes 和 K. Negishi：“核糖核苷酸类似物对遗传信息的干扰”核酸研讨会系列。

K.Moriyama: "Synthesis and RNA polymerase incorporation of the degenarate ribonucleotide analogue rPTP" Nucleic Acids Res.26. 2105-2111 (1998)

K.Moriyama：“简并核糖核苷酸类似物 rPTP 的合成和 RNA 聚合酶掺入”核酸 Res.26。

Kei Moriyama: "Disturbance of genetic information by a ribonucleotide analogue"Nucleic Acids Symposium Series. No. 42. 131-132 (1999)

Kei Moriyama：“核糖核苷酸类似物对遗传信息的干扰”核酸研讨会系列。

K. Moriyama, K. Negishi, M. S. J. Briggs, C. L. Smith, F. Hills, M. J. Churcher, D. M. Brown and D. Loakes: "Synthesis and RNA polymerase incorporation of the degenarate ribonucleotide analogue rPTP"Nucleic Acids Res.. 26. 2105-2111 (1998)

K. Moriyama、K. Negishi、M. S. J. Briggs、C. L. Smith、F. Hills、M. J. Churcher、D. M. Brown 和 D. Loakes：“简并核糖核苷酸类似物 rPTP 的合成和 RNA 聚合酶掺入”核酸研究 26. 2105-

Kei Moriyama: "Disturbance of genetic information by a ribonucleotide analogue"Nucleic Acids Symposium Series. No.42. 131-132 (1999)

Kei Moriyama：“核糖核苷酸类似物对遗传信息的干扰”核酸研讨会系列。