Identification of a mutation in the Bacillus subtilis S-adenosyhnethionine synthetase gene that results in derepression of S-Box gene expression
Identification of a mutation in the Bacillus subtilis S-adenosyhnethionine synthetase gene that results in derepression of S-Box gene expression
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DOI：
10.1128/jb.188.10.3674-3681.2006
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发表时间：
2006-05-01
影响因子：
3.2
通讯作者：
Henkin, Tina M.
中科院分区：
文献类型：
--
作者：
McDaniel, Brooke A.;Grundy, Frank J.;Henkin, Tina M.
Genes in the S-box family are regulated by binding of S-adenosylmethionine (SAM) to the 5' region of the mRNA of the regulated gene. SAM binding was previously shown to promote a rearrangement of the RNA structure that results in premature termination of transcription in vitro and repression of expression of the downstream coding sequence. The S-box RNA element therefore acts as a SAM-binding riboswitch in vitro. In an effort to identify factors other than SAM that could be involved in the S-box regulatory mechanism in vivo, we searched for trans-acting mutations in Bacillus subtilis that act to disrupt repression of S-box gene expression during growth under conditions where SAM pools are elevated. We identified a single mutant that proved to have one nucleotide substitution in the metK gene, encoding SAM synthetase. This mutation, designated metK10, resulted in a 15-fold decrease in SAM synthetase activity and a 4-fold decrease in SAM concentration in vivo. The metK10 mutation specifically affected S-box gene expression, and the increase in expression under repressing conditions was dependent on the presence of a functional transcriptional antiterminator element. The observation that the mutation identified in this search affects SAM production supports the model that the S-box RNAs directly monitor SAM in vivo, without a requirement for additional factors.
