A global transcriptional regulator in Thermococcus kodakaraensis controls the expression levels of both glycolytic and gluconeogenic enzyme-encoding genes
A global transcriptional regulator in Thermococcus kodakaraensis controls the expression levels of both glycolytic and gluconeogenic enzyme-encoding genes
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DOI：
10.1074/jbc.m703424200
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发表时间：
2007-11-16
影响因子：
4.8
通讯作者：
Imanaka, Tadayuki
中科院分区：
文献类型：
--
作者：
Kanai, Tamotsu;Akerboom, Jasper;Imanaka, Tadayuki
我们确定了一种新的调节器，Thermococcales糖酵解调节器（TGR），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Pyrococcus furiosus TrmB（PF 1743）相似（28%相同），这是一种调节海藻糖/麦芽糖ATP结合盒转运蛋白基因的转录抑制因子，但与Pyrococcus furiosus（PF 0124）中的TrmB parasites更密切相关（67%）。与野生型菌株相比，生长的tgr破坏菌株（Δ tgr）显示出显着降低的生长速率下产气条件下，而糖酵解条件下观察到相当的生长速率。全基因组微阵列分析显示，几乎所有的基因的转录水平相关的糖酵解和麦芽糖糊精代谢是在相对较高的水平，在三角洲tgr突变体，即使在产气条件下。在这些条件下，Δ tgr突变体也显示出致突变基因的转录激活缺陷，表明Tgr既作为激活因子又作为抑制因子发挥作用。由Tgr调控的基因包含先前鉴定的序列基序，即热球菌糖酵解基序（TGM）。TGM在促细胞生成启动子中位于转录因子B应答元件（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。我们的研究结果有力地表明，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，糖酵解和产酶代谢在T。kodakaraensis通过其直接结合TGM。
We identified a novel regulator, Thermococcales glycolytic regulator (Tgr), functioning as both an activator and a repressor of transcription in the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1. Tgr (TK1769) displays similarity (28% identical) to Pyrococcus furiosus TrmB (PF1743), a transcriptional repressor regulating the trehalose/maltose ATP-binding cassette transporter genes, but is more closely related (67%) to a TrmB paralog in P. furiosus (PF0124). Growth of a tgr disruption strain (Delta tgr) displayed a significant decrease in growth rate under gluconeogenic conditions compared with the wild-type strain, whereas 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 Delta tgr mutant even under gluconeogenic conditions. The Delta tgr 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, the Thermococcales glycolytic motif (TGM). The TGM was positioned upstream of the Transcription factor B-responsive element (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.