TRANSFER-RNA AS A POSITIVE REGULATOR OF TRANSCRIPTION ANTITERMINATION IN BACILLUS-SUBTILIS
TRANSFER-RNA AS A POSITIVE REGULATOR OF TRANSCRIPTION ANTITERMINATION IN BACILLUS-SUBTILIS
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DOI：
10.1016/0092-8674(93)80049-k
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发表时间：
1993-08-13
期刊：
影响因子：
64.5
通讯作者：
HENKIN, TM
中科院分区：
文献类型：
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作者：
GRUNDY, FJ;HENKIN, TM
大多数芽孢杆菌tRNA合成酶基因受共同的转录抗终止机制调控，但对同源氨基酸的限制有单独的反应。这些基因的mRNA先导区表现出广泛的结构保守性，在每个结构的相同位置都有一个特定于适当氨基酸的单个密码子。tyrS基因的这一序列从UAC（酪氨酸）改变为UUC（苯丙氨酸），导致酪氨酸限制诱导丧失，转而由苯丙氨酸限制诱导。在密码子上游插入一个额外的碱基并没有改变调控，表明这是一种非翻译机制。无义密码子导致在赖氨酸-tRNA无义抑制突变体中被抑制的不可诱导表型，表明tRNA发挥了效应。
Most Bacillus tRNA synthetase genes are regulated by a common transcription antitermination mechanism but respond individually to limitation for the cognate amino acid. The mRNA leader regions of these genes exhibit extensive structural conservation, with a single codon specific for the appropriate amino acid at the identical position in each structure. Alteration of this sequence in the tyrS gene from UAC (tyrosine) to UUC (phenylalanine) resulted in loss of induction by tyrosine limitation and a switch to induction by phenylalanine limitation. Insertion of an extra base immediately upstream of the codon did not alter regulation, indicating a nontranslational mechanism. A nonsense codon resulted in an uninducible phenotype that was suppressible in a lysyl-tRNA nonsense suppressor mutant, indicating that tRNA acts as an effector.