Coordinated Regulation of Gene Expression for Carotenoid Metabolism in Chlamydomonas reinhardtii  

作　　者：Tian-Hu Sun Cheng-Qian Liu Yuan-Yuan Hui Wen-Kai Wu Zhi-Gang Zhou Shan Lu 

机构地区：[1]State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, China [2]College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China [3]Discipline Crossing Center, Nanjing University, Nanjing 210093, China

出　　处：《Journal of Integrative Plant Biology》2010年第10期868-878,共11页植物学报（英文版）

基　　金：supported by the State Key Basic Research and Development Plan of China(2007CB108800);the National Natural Science Foundation of China (30771167 and 90817002);supported by the National Undergraduate Innovation Program and the National Natural Science Foundation of China (J0730641)

摘　　要：Carotenoids are important plant pigments for both light harvesting and photooxidation protection. Using the model system of the unicellular green alga Chlamydomonas reinhardtii, we characterized the regulation of gene expression for carotenoid metabolism by quantifying changes in the transcript abundance of dxs, dxr and ipi in the plastidic methylerythritol phosphate pathway and of ggps, psy, pds, Icyb and bchy, directly involved in carotenoid and metabolite treatments. The expression of these metabolism, under different photoperiod, light genes fluctuated with light/dark shifting. Light treatment also promoted the accumulation of transcripts of all these genes. Of the genes studied, dxs, ggps and Icyb displayed the typical circadian pattern by retaining a rhythmic fluctuation of transcript abundance under both constant light and constant dark entrainments. The expression of these genes could also be regulated by metabolic intermediates. For example, ggps was significantly suppressed by a geranylgeranyl pyrophosphate supplement and ipi was upregulated by isopentenyl pyrophosphate. Furthermore, CrOr, a C. reinhardtii homolog of the recently characterized Or gene that accounts for carotenoid accumulation, also showed co-expression with carotenoid biosynthetic genes such as pds and Icyb. Our data suggest a coordinated regulation on carotenoid metabolism in C. reinhardtii at the transcriptional level.Carotenoids are important plant pigments for both light harvesting and photooxidation protection. Using the model system of the unicellular green alga Chlamydomonas reinhardtii, we characterized the regulation of gene expression for carotenoid metabolism by quantifying changes in the transcript abundance of dxs, dxr and ipi in the plastidic methylerythritol phosphate pathway and of ggps, psy, pds, Icyb and bchy, directly involved in carotenoid and metabolite treatments. The expression of these metabolism, under different photoperiod, light genes fluctuated with light/dark shifting. Light treatment also promoted the accumulation of transcripts of all these genes. Of the genes studied, dxs, ggps and Icyb displayed the typical circadian pattern by retaining a rhythmic fluctuation of transcript abundance under both constant light and constant dark entrainments. The expression of these genes could also be regulated by metabolic intermediates. For example, ggps was significantly suppressed by a geranylgeranyl pyrophosphate supplement and ipi was upregulated by isopentenyl pyrophosphate. Furthermore, CrOr, a C. reinhardtii homolog of the recently characterized Or gene that accounts for carotenoid accumulation, also showed co-expression with carotenoid biosynthetic genes such as pds and Icyb. Our data suggest a coordinated regulation on carotenoid metabolism in C. reinhardtii at the transcriptional level.

分 类 号：Q562[生物学—生物化学] Q591