Comprehensive study on transcriptional network system in the photoautotrophic cyanobacteria Synechococcusstrains

光合自养蓝细菌聚球藻转录网络系统的综合研究

基本信息

批准号：
13206027
负责人：
SUGITA Mamoru
金额：
$ 37.31万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13206027/
关键词：
cyanobacteria transcription network two-component regulatory system nitrate transport system DNA chip photoautotroph circadian rhythm clock gene ゲノム光合成遺伝子炭酸水素イオン能動輸送体 Synechococcus 6301株 Synechococcus 7942株 Synechocystis 6803株

项目摘要

(1) The entire genome of a unicellular cyanobacterium, Synechococcus sp. strain PCC 6301, was sequenced. The genome consisted of a circular chromosome 2,696,255 bp long. A total of 2525 potential protein-encoding genes, two sets of rRNA genes, 45 tRNA genes representing 42 tRNA species and several genes, for small structural RNAs were assigned to the chromosome. Thirty-seven genes for the proteins involved in two-component regulatory system were also annotated. Ten percent of all the protein genes lacked significant similarity to genes for predicted proteins in the public, indicating the genes unique to Synechococcus PCC6301. We constructed high-density DNA microarrays (Affimetrix Gene Chip) of Synechococcus PCC6301 as a tool for comprehensive analysis of transcriptional network in cyanobacteria.(2) We identified three genes responsible for the latent transport activity for nitrate: ltnA, which encodes a response regulator with no effector domain; ltnB, which encodes a hybrid histidine kinase with two receiver domains; and ltnT, which encodes a sulfate permease-like protein with a putative cyclic nucleoside monophosphate (cNMP)-binding domain.(3) Circadian clock of cyanobacteria was considered to be composed of negative feedback regulation of kaiBC expression. We demonstrated that KaiC phosphorylation state oscillated even without kaiBC messenger RNA accumulation under continuous dark conditions. Moreover, kinetic profiles in the ratio of KaiC autophosphorylation-dephosphorylation were also temperature compensated in vitro. Thus, the cyanobacterial clock can keep time independent of de novo transcription and translation processes. Furthermore, we have reconstituted the self-sustainable oscillation of KaiC phosphorylation in vitro. The period of the in vitro oscillation was stable and the circadian periods observed in vivo in KaiC mutant strains were consistent with those measured in vitro.

（1）单细胞蓝细菌的整个基因组，Synechococcus sp。测序菌株PCC 6301。基因组由2,696,255 bp的圆形染色体组成。总共有2525个潜在的蛋白质编码基因，两组RRNA基因，45个代表42种TRNA物种的TRNA基因和几种基因，用于小型结构RNA。还注释了参与两组分组调节系统的蛋白质的37个基因。在所有蛋白质基因中，百分之十的蛋白质基因与公众预测蛋白的基因缺乏显着相似性，表明Syechococcus PCC6301所独有的基因。我们构建了Syechococcus PCC6301的高密度DNA微阵列（Affimetrix基因芯片），作为用于全面分析蓝细菌转录网络的工具。（2）我们确定了硝酸盐的潜在转运活性的三个基因：LTNA：LTNA，ltna，该基因响应调节器，该基因响应调节器与无效的效应域编码无效应的效应域，以实现效应域编码； LTNB，它编码具有两个接收域的混合组氨酸激酶； LTNT和LTNT用假定的环状核苷单磷酸（CNMP）结合结构域编码硫酸盐渗透酶样蛋白。（3）蓝细菌的昼夜节律被认为是由KAIBC表达的负反馈调节组成的。我们证明，即使没有KAIBC Messenger RNA在连续的黑暗条件下，KAIC磷酸化状态也振荡。此外，在体外还补偿了KAIC自磷酸化 - 二磷酸化比率的动力学特征。因此，蓝细菌时钟可以保持时间独立于从头转录和翻译过程。此外，我们已经重构了体外KAIC磷酸化的自我维持的振荡。体外振荡的周期是稳定的，在KAIC突变菌株中体内观察到的昼夜节律与体外测量的时期相一致。