Preliminary Validation Of The Two Cyanobacteria True Karyotype Of Ser / Thr Kinase Gene Function

Serine/threonine kinases (STKs) have been shown playing key roles in the signal transduction systems of eukaryotes. For that reason, STKs are targets of drugs for curing varieties of human diseases such as tumor and tuberculosis. STKs have been found in an increasing number of prokaryotes since 1990s, also showing important roles in signal transduction. In this study, functions of several eukaryotic STKs in Synechococcus sp. PCC7942 and Spirulina platensis are investigated primarily.Cyanobacteria have the characters of both bacteria and plant. The mature gene transformation system has made cyanobacteria frequently used for the study of eukaryotic genes. Synechococcus sp. PCC7942 is a kind of unicellular cyanobacteria in freshwater, which can be transformed naturally and is the model specie of molecular genetics of cyanobacteria. Serine/threonine kinase of stk196 in Synechococcus sp. PCC7942 was indicated to be involved in adaptation to high temperature stress according mutant and semi-quantitative RT-PCR analysis in this study. Spirulina platensis is a kind of filamentous cyanobacteria, which is noticeable in their nutritional potential. By using semi-quantitative RT-PCR,the expressions of four serine/threonine kinase genes, whose products were predicted to be located in the membrane, were investigated under optimal growth temperature and after treatments of low temperatures and high temperatures, separately. The results showed that the expression of stk2103 was down-regulated under low temperatures and up-regulated under high temperatures. It indicated that the expression of stk2103 has a close relationship with the temperature tolerance of Spirulina platensis.The study of eukaryotic STKs in cyanobacteria may provide important clues for further study of STKs in eukaryotes and for the anti-stress study of plants.