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Elucidation of gene regulation systems based on genome analysis

基于基因组分析阐明基因调控系统

基本信息

批准号：
17350083
负责人：
ATOMI Haruyuki
金额：
$ 9.66万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17350083/
关键词：
hyperthermophile archaea Thermococcus promoter transcription genome regulation repressor

项目摘要

We have identified a novel regulator, Tgr (Thermococcales glycolytic regulator), functioning as both an activator and a repressor of transcription in the hyperthermophilic archaeon Thermococcus kodakaraensis KOD 1. Tgr (TK1769) displays similarity (28% identical) to Pyrococcus furiosus TrmB (PF1743), a transcriptional repressor regulating the trehalose/maltose ABC transporter genes, but is more closely related (67%) to a TrmB paralog in P.furiosus (PF0124). Growth of a tgr disruption strain (Δtgr) displayed a significant decrease in growth rate under gluconeogenic conditions compared to the wild-type strain, while comparable growth rates were observed under glycolytic conditions. A whole genome microarray analysis revealed that transcript levels of almost all genes related to glycolysis and maltodextrin metabolism were at relatively high levels in the Δtgr mutant even under gluconeogenic conditions. The Δtgr mutant also displayed defects in the transcriptional activation of gluconeogenic genes under these conditions, indicating that Tgr functions as both an activator and a repressor. Genes regulated by Tgr contain a previously identified sequence motif, TGM (Thermococcales glycolytic motif). The TGM was positioned upstream of the BRE/TATA sequence in gluconeogenic promoters, and downstream of it in glycolytic promoters. Electrophoretic mobility shift assay indicated that recombinant Tgr protein specifically binds to promoter regions containing a TGM. Tgr was released from the DNA when maltotriose was added, suggesting that this sugar is most likely the physiological effector. Our results strongly suggest that Tgr is a global transcriptional regulator that simultaneously controls, in response to sugar availability, both glycolytic and gluconeogenic metabolism in T.kodakaraensis via its direct binding to the TGM.

我们已经确定了一种新的调节器，TGR（Thermococcales糖酵解调节器），作为一个激活剂和转录抑制剂的超嗜热古菌Thermococcus kodakaraensis KOD 1。Tgr（TK 1769）与强烈火球菌TrmB（PF 1743）（一种调节海藻糖/麦芽糖ABC转运蛋白基因的转录抑制因子）具有相似性（28%相同），但与强烈火球菌中的TrmB paraminase（PF 0124）更密切相关（67%）。与野生型菌株相比，tgr破坏菌株（Δtgr）的生长在产酶条件下显示出生长速率显著降低，而在糖酵解条件下观察到相当的生长速率。全基因组芯片分析显示，几乎所有与糖酵解和麦芽糖糊精代谢相关的基因的转录水平在Δtgr突变体中处于相对较高的水平，即使在产气条件下。在这些条件下，Δtgr突变体也显示出致突变基因转录激活的缺陷，表明Tgr既是激活子又是阻遏子。由Tgr调控的基因包含先前鉴定的序列基序，TGM（热球菌糖酵解基序）。TGM在促酵启动子中位于BRE/TATA序列的上游，在糖酵解启动子中位于其下游。电泳迁移率变动分析表明，重组Tgr蛋白特异性结合到启动子区含有TGM。当加入麦芽三糖时，Tgr从DNA中释放出来，这表明这种糖最有可能是生理效应物。我们的研究结果强烈表明，Tgr是一个全球性的转录调节因子，同时控制，在响应糖的可用性，糖酵解和产碱代谢在T.柯达卡拉通过其直接结合到TGM。