An rne-1 pnp-7 double mutation suppresses the temperature-sensitive defect of lacZ gene expression in a divE mutant

被引:7
作者
Aiso, T [1 ]
Ohki, R [1 ]
机构
[1] Kyorin Univ, Sch Hlth Sci, Dept Biol Mol, Tokyo 192, Japan
关键词
D O I
10.1128/JB.180.6.1389-1395.1998
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
A divE mutant, which has a temperature-sensitive mutation in the tRNA(1)(Ser) gene, exhibits differential loss of the synthesis of certain proteins, such as beta-galactosidase and succinate dehydrogenase, at nonpermissive temperatures, In Escherichia coli, the UCA codon is recognized only by tRNA(1)(Ser). Several genes containing UCA codons are normally expressed after a temperature shift to 42 degrees C in the divE mutant, Therefore, it is unlikely that the defect in protein synthesis at 42 degrees C is simply caused by a defect in the decoding function of the mutant tRNA(1)(Ser). In this study, we sought to determine the cause of the defect in lacZ gene expression in the divE mutant, It has also been shown that the defect in lacZ gene expression is accompanied by a decrease in the amount of lacZ mRNA, To examine whether inactivation of mRNA degradation pathways restores the defect in lacZ gene expression, we constructed divE mutants containing rne-1, rnb-500, and pnp-7 mutations in various combinations, We found that the defect was almost completely restored by introducing an rne-1 pnp-7 double mutation into the divE mutant, Northern hybridization analysis showed that the rne-1 mutation stabilized lacZ mRNA, whereas the pnp-7 mutation stabilized mutant tRNA(1)(Ser), at 44 degrees C, We present a mechanism that may explain these results.
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页码:1389 / 1395
页数:7
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