DNA sequence and complementation analysis of a mutation in the rplX gene from Escherichia coli leading to loss of ribosomal protein L24
DNA sequence and complementation analysis of a mutation in the rplX gene from Escherichia coli leading to loss of ribosomal protein L24
复制标题
大肠杆菌 rplX 基因突变导致核糖体蛋白 L24 缺失的 DNA 序列和互补分析
DOI：
10.1128/jb.163.3.890-894.1985
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发表时间：
1985
影响因子：
3.2
通讯作者：
J. Schnier
中科院分区：
文献类型：
--
作者：
K. Nishi;E. Dabbs;J. Schnier
大肠杆菌中的突变会导致核糖体蛋白L24的丢失，严重损害生长，并产生对温度敏感的表型。突变发生在蛋白L24的基因rplX中，其原因是rplX第61位的AAA密码子变为TAA终止密码子，从而产生了一个20个氨基酸的多肽，而不是野生型L24蛋白的104个氨基酸。克隆了该突变体的3个耐温、生长快的假恢复系的rplX基因，并进行了序列测定。发现它们在TAA密码子上有不同的碱基替换，导致了完整大小的蛋白质L24部分的重现。至少含有SPC启动子和完整的L14和L24基因的几个质粒可以实现对反式生长缓慢的补充。含有rplX末端基因的质粒可以进一步刺激生长，当整个SPC操纵子和α操纵子存在时，野生型就会出现。在所有的病例中，L24蛋白都通过质粒表达。因此，缓慢的生长可以用延伸到α操纵子的极性来解释。然而，温度敏感性不能被反式中的任何一个质粒所补充，尽管我们发现这种表型是由rplX基因的突变引起的。
A mutation in Escherichia coli leads to the loss of ribosomal protein L24, severely impaired growth, and a temperature-sensitive phenotype. The mutation was shown to be in rplX, the gene for protein L24, and was due to the alteration of an AAA codon to a TAA stop codon at position 61 in rplX that resulted in a 20-amino acid peptide instead of the 104 amino acids of wild-type L24 protein. rplX genes from three temperature-resistant and fast growing pseudorevertants of the mutant were cloned and sequenced. They were found to have different base substitutions in the TAA codon, resulting in the reappearance of a full-sized protein L24 moiety. Complementation of the slow growth in trans could be achieved with several plasmids containing at least the spc promoter and intact L14 and L24 genes. Plasmids containing genes distal to rplX could further stimulate growth, and the wild type arose when the entire spc operon and the alpha operon were present. In all cases, protein L24 was expressed by the plasmids. Therefore, slow growth could be explained by polarity extending to the alpha operon. However, temperature sensitivity could not be complemented by any of the plasmids in trans, although we found that this phenotype was caused by the mutation in the rplX gene.