摘要
The central oscillator of circadian clock in cyanobacterium,Synechococcus elongatus PCC 7942,is composed of kai A,kai B,kai C proteins. Many researches confirmed that this self-sustained intracellular circadian clock,so-called Kai clock,have played a pivotal role in the generation and calibration of the time clue for the circadian rhythm in cyanobacterial metabolism. Some proteins,such as Sas A、Lab A、Cik A、Rap A,are considered to be the key switches that have operated the output pathways of Kai clock. Peroxiredoxins(Prxs) in short,are families of thiol-specific antioxidant protein,which have be convinced to exert an important function in the whole antioxidant defense system of cyanobacteria,the rhythmic changes redox state of 2Cys-Prx are proved as a conserved non-transcriptional rhythmic marker. To test the relationship between the Kai clock and the PRX-SO_(2/3) rhythmic marker,the expression patterns of clock genes were detected of by q PCR method in Wild-type(WT) and prx-2cys gene knockout(Δprx-2cys) trains under different light intensity. The results demonstrated that under the natural light condition(100μEm~(-2)s~(-1)),the rhythmic expression phenotype of the central clock genes were not affected by whether the prx-2cys gene were knocked out in S.elongatus PCC 7942 cells,while the expression patterns of the genes operating the output pathway were slightly affected. Interestingly,under a high light stressed condition(400μEm~(-2)s~(-1)),the expression patterns of the output pathway genes were severely affected both in WT and Δprx-2cys strains. The circadian rhythmic expression pattern of the central clock genes nearly disappeared in WT strains,while more robust rhythmic expression profiles of sas A 、 lab A 、 cik A 、 rap A were restored inΔprx-2cys cells by an unknown method.
The central oscillator of circadian clock in cyanobacterium,Synechococcus elongatus PCC 7942,is composed of kai A,kai B,kai C proteins. Many researches confirmed that this self-sustained intracellular circadian clock,so-called Kai clock,have played a pivotal role in the generation and calibration of the time clue for the circadian rhythm in cyanobacterial metabolism. Some proteins,such as Sas A、Lab A、Cik A、Rap A,are considered to be the key switches that have operated the output pathways of Kai clock. Peroxiredoxins(Prxs) in short,are families of thiol-specific antioxidant protein,which have be convinced to exert an important function in the whole antioxidant defense system of cyanobacteria,the rhythmic changes redox state of 2Cys-Prx are proved as a conserved non-transcriptional rhythmic marker. To test the relationship between the Kai clock and the PRX-SO_(2/3) rhythmic marker,the expression patterns of clock genes were detected of by q PCR method in Wild-type(WT) and prx-2cys gene knockout(Δprx-2cys) trains under different light intensity. The results demonstrated that under the natural light condition(100μEm~(-2)s~(-1)),the rhythmic expression phenotype of the central clock genes were not affected by whether the prx-2cys gene were knocked out in S.elongatus PCC 7942 cells,while the expression patterns of the genes operating the output pathway were slightly affected. Interestingly,under a high light stressed condition(400μEm~(-2)s~(-1)),the expression patterns of the output pathway genes were severely affected both in WT and Δprx-2cys strains. The circadian rhythmic expression pattern of the central clock genes nearly disappeared in WT strains,while more robust rhythmic expression profiles of sas A 、 lab A 、 cik A 、 rap A were restored inΔprx-2cys cells by an unknown method.
引文