The T box and S box transcription termination control systems
The T box and S box transcription termination control systems
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DOI：
10.2741/908
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发表时间：
2003-01-01
影响因子：
3.1
通讯作者：
Henkin, TM
中科院分区：
文献类型：
--
作者：
Grundy, FJ;Henkin, TM
T盒和S盒转录终止控制系统广泛用于控制革兰氏阳性细菌中的基因表达，但在革兰氏阴性生物中很少见。由于一级序列和结构元件的高度保守性，这两个系统都可以在基因组数据中被识别。 T盒系统调节多种氨基酸相关基因，而S盒系统专门调节与蛋氨酸代谢相关的基因。虽然这两个系统都涉及转录提前终止水平的基因调控，但所采用的分子机制却非常不同。在T盒系统中，通过与同源不带电荷的tRNA相互作用来稳定前导序列中的抗终止子结构来诱导表达；这可以防止竞争性终止子螺旋的形成，从而允许合成全长 mRNA。保守前导特征的破坏会导致通读丢失。在S盒系统中，领导者的反终结者形式是更稳定的形式。竞争性抗抗终止子在甲硫氨酸中生长期间必须通过未知因子稳定，以防止抗终止子形成，从而形成终止子螺旋。保守前导元件的破坏导致组成型表达。
The T box and S box transcription termination control systems are widely used for control of gene expression in Gram-positive bacteria, but are rare in Gram-negative organisms. Both of these systems can be recognized in genomic data because of high conservation of primary sequence and structural elements. The T box system regulates a variety of amino acid-related genes, while the S box system is dedicated to genes involved in methionine metabolism. While both systems involve gene regulation at the level of premature termination of transcription, the molecular mechanisms employed are very different. In the T box system, expression is induced by stabilization of an antiterminator structure in the leader by interaction with the cognate uncharged tRNA; this prevents formation of the competing terminator helix, allowing synthesis of the full-length mRNA. Disruption of conserved leader features results in loss of readthrough. In the S box system, the antiterminator form of the leader is the more stable form. A competing anti-antiterminator must be stabilized by an unknown factor during growth in methionine to prevent formation of the antiterminator, thereby allowing formation of the terminator helix. Disruption of conserved leader elements results in constitutive expression.