THE STRUCTURAL GENE (TRMD) FOR THE TRANSFER RNA(M1G)METHYLTRANSFERASE IS PART OF A 4 POLYPEPTIDE OPERON IN ESCHERICHIA-COLI K-12
THE STRUCTURAL GENE (TRMD) FOR THE TRANSFER RNA(M1G)METHYLTRANSFERASE IS PART OF A 4 POLYPEPTIDE OPERON IN ESCHERICHIA-COLI K-12
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DOI：
10.1007/bf00330047
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发表时间：
1982-01-01
期刊：
影响因子：
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通讯作者：
BJORK, GR
中科院分区：
文献类型：
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作者：
BYSTROM, AS;BJORK, GR
trmD基因是tRNA（m1 G）-甲基转移酶的结构基因，被证明是多顺反子操纵子的一部分。一个4.6 kb的SalI-EcoRI染色体DNA片段含有trmD基因（Bystroem and Bjoerk 1982）。通过亚克隆、缺失作图和转座子Tn 5插入pBY 03质粒中，建立了大肠杆菌trmD区的基因结构。coli染色体。使用微细胞系统分析不同质粒衍生物的蛋白质产物表达。这些分析确定了编码6种多肽的基因的组织为SalI 1 -48 K-13 K-25 K-31 K-15 K-16 K-EcoRI 1。31 K多肽是tRNA（m1 G）甲基转移酶。trmD操纵子编码4种多肽：13 K-25 K-31 K（trmD）-15 K，转录方向为13 K（启动子近端）至15 K（启动子远端）。在trmD基因和15 K产物编码基因之间可能存在一个弱的内部启动子。在小细胞系统中来自该操纵子的表达水平似乎不遵循正常极性，因为我们观察到13 K、25 K和15 K产物的高表达，但内部trmD基因的低表达。
The trmD gene, which is the structural gene for the tRNA(m1G)-methyltransferase, is shown to be part of a polycistronic operon. A 4.6 kb [kilobase] SalI-EcoRI chromosomal DNA fragment contains the trmD gene (Bystroem and Bjoerk 1982). Subclonings, deletion mapping and [transposon] Tn5 insertions into plasmic pBY03 established the gene organization of the trmD area on the E. coli chromosome. The different plasmid derivatives were analyzed for expression of protein products using the minicell system. Such analyses established the organization of genes encoding 6 polypeptides to be SalI1-48 K-13 K-25 K-31 K-15 K-16 K-EcoRI1. The 31 K polypeptide was the tRNA(m1G)methyltransferase. The trmD operon encodes for 4 polypeptides; 13 K-25 K-31 K(trmD)-15 K and the direction of transcription are from 13 K (promoter proximal) to 15 K (promoter distal). There might be a weak internal promoter between the trmD gene and the gene encoding the 15 K product. The level of expression from this operon in the minicell system does not seem to follow normal polarity since we observed high expression of 13 K, 25 K and 15 K products but low expression of the internal trmD gene.