Roles of molecular chaperones for regulation of genes and assembly of photosynthetic apparatus

1.新型分子伴侣Orf7.5Orf7.5对蓝藻groESL1转录的正调控作用Orf7.5Orf7.5是一种能提高聚球藻groESL1启动子活性的正转录因子。PCC7942尤其是在热休克条件下与主要的西格玛因子相互作用。2.蓝藻HSPA热休克诱导的转录后调控外生聚球藻HSPA基因编码一个小的热休克蛋白。说明HspA热休克诱导是转录后自身控制的。3.HspA细胞功能与野生型聚球藻的比较分析。PCC6803及其hspA缺失突变株表明hspA参与了盐胁迫的调控。通过将HSPA原性表达菌株ECT16-1与参考菌株ECT进行比较，研究了HSPA在胁迫条件下的作用。高温或强化…条件下蓝藻超微结构的稳定性4.HtpG的细胞功能我们阐明了HSPA在聚球藻中的结构性表达能否在功能上取代HtpG。PCC 7942。HtpG突变体在胁迫条件下没有改善缺陷，这表明HtpG的细胞功能可能与HspA不同。5.分子伴侣在藻胆体组装中的作用我们证明了HSPA直接与聚球藻的藻蓝蛋白相互作用。PCC7942细胞体外培养。我们还发现了藻胆体的连接体多肽与HtpG之间的特异性相互作用，这些结果表明分子伴侣通过稳定藻蓝蛋白和连接体多肽在藻胆体组装中发挥重要作用。6.蓝藻isiABC操纵子在保护氧化和热胁迫中的作用isiAB操纵子编码CP43‘和黄素，形成光合作用装置。我们发现，isiABC操纵子不仅在铁胁迫下发挥重要作用，而且在氧化和热胁迫等多重胁迫下也发挥重要作用。较少

1.A positive control of the cyanobacterial groESL1 transcription by a novel molecular chaperone, Orf7.5Orf7.5 was a positive transcription factor which increases the activity of the groESL1 promoter of Synechococcus sp. PCC 7942 especially under heat shock conditions by interacting with the major sigma factor.2.Post-transcriptional regulation of the cyanobacterial hspA heat-shock inductionThe hspA gene from Synechococcus vulcanus encodes a small heat-shock protein. We showed that the hspA heat-shock induction is self-controlled post-transcriptionally.3.Cellular functions of HspAComparative analyses of the wild-type Synechocystis sp. PCC 6803 and its hspA null mutant strain showed that hspA is involved in salt-stress management. The role of HspA under stress conditions was investigated comparing Synechococcus strain ECT16-1, which constitutively expresses HspA, with the reference strain ECT. HspA conferred the cyanobacterium ultrastructural stability under high temperature or intensive … More light stress.4.Cellular functions of HtpGWe elucidated whether constitutive expression of HspA can functionally replace HtpG in Synechococcus sp. PCC 7942. It did not improve defects of an htpG mutant under stress conditions, indicating that cellular function of HtpG may differ from that of HspA.5.Roles of molecular chaperone for the phycobilisome assemblyWe showed that HspA interacts directly with phycocyanins from Synechococcus sp. PCC 7942 in vitro. We also showed a specific interaction between a linker polypeptide of phycobilisome and HtpG These results indicate that the molecular chaperones play important roles in the phycobilisome assembly by stabilizing phycocyanins and the linker polypeptide.6.Roles of the cyanobacterial isiABC operon in protection from oxidative and heat stressesThe isiAB operon encodes CP43' and flavodoxin which form the photosynthetic apparatus. We showed that the isiABC operon plays essential roles not only under iron stress, but also under multiple stresses such as oxidative and heat stresses. Less