ISOLATION OF DEOXYRIBONUCLEIC ACID METHYLASE MUTANTS OF ESCHERICHIA-COLI K-12
ISOLATION OF DEOXYRIBONUCLEIC ACID METHYLASE MUTANTS OF ESCHERICHIA-COLI K-12
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DOI：
10.1128/jb.114.3.1143-1150.1973
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发表时间：
1973-01-01
影响因子：
3.2
通讯作者：
MORRIS, NR
中科院分区：
文献类型：
--
作者：
MARINUS, MG;MORRIS, NR
通过检测未经筛选的诱变细胞克隆制备的核酸接受野生型粗提物中甲基的能力，从大肠杆菌-12中分离到14个脱氧核糖核酸(DNA)和10个核糖核酸(RNA)甲基化突变体。其中11个DNA甲基化突变体缺乏5-甲基胞嘧啶(5-MEC)，被命名为DCM。3个DNA甲基化突变体缺乏N6-甲基腺嘌呤(N6-mea)，命名为Dam。对突变株的胞嘧啶：S-腺苷蛋氨酸和腺嘌呤：S-腺苷蛋氨酸甲基转移酶的活性进行了检测。除了一个例外，所有突变体的活性都降低或缺失。DCM突变位于36-37分钟，DAM突变位于遗传图谱的60-66分钟区域。DCM突变体没有明显的相关表型异常。Dam突变体在限制λ的能力上存在缺陷。没有一种突变具有致命性。
Fourteen deoxyribonucleic acid (DNA) and 10 ribonucleic acid (RNA) methylation mutants were isolated fromEscherichia coliK-12 by examining the ability of nucleic acids prepared from clones of unselected mutagenized cells to accept methyl groups from wild-type crude extract. Eleven of the DNA methylation mutants were deficient in 5-methylcytosine (5-MeC) and were designated Dcm. Three DNA methylation mutants were deficient in N6-methyladenine (N6-MeA) and were designated Dam. Extracts of the mutants were tested for DNA-cytosine:S-adenosylmethionine and DNA-adenine:S-adenosylmethionine methyltransferase activities. With one exception, all of the mutants had reduced or absent activity. A representative Dcm mutation was located at 36 to 37 min and a representative Dam mutation was located in the 60-to 66-min region on the genetic map. The Dcm mutants had no obvious associated phenotypic abnormality. The Dam mutants were defective in their ability to restrict λ. None of the mutations had the effect of being lethal.