Identification of oxygen dependent signalling pathways in the green alga Chlamydomonas reinhardtii by Digital Gene Expression Tag Profiling

本项目旨在鉴定单细胞绿藻莱茵衣藻（Chlamydomonas reinhardtii）中涉及氧（O2）信号的基因，这是一种被充分研究的参考藻类，其基因组已被测序。为此，利用Illumina平台上的下一代测序技术（RNA-seq）记录了逐渐进入缺氧状态的C. reinhardtii野生型培养物的全基因组转录谱。渐进式采样可以识别出在O2开始受限的时间点上差异表达的基因，这些基因的蛋白质产物因此可能在O2信号传导中发挥作用。最初的项目计划已被修改，包括几个缺乏Crr1功能的莱因哈特氏菌突变株，Crr1是莱因哈特氏菌中铜（Cu）和缺氧信号的关键转录调节因子。Merchant （UCLA，美国）和Happe （RUB，德国）团队最近尚未发表的研究结果表明，Crr1可能在O2依赖性基因调控中发挥比预期更重要的作用。因此，比较野生型和crr1突变株在不同O2浓度下的转录组，可以让我对C. reinhardtii的O2信号传导有更详细的了解。延长的项目期间将允许与当地计算生物学家合作对序列数据进行深入分析。

This project aims at identifying genes involved in oxygen (O2) signaling in the unicellular green alga Chlamydomonas reinhardtii, a well-studied reference alga whose genome has been sequenced. For this purpose, whole-genome transcription profiles of C. reinhardtii wild type cultures passing gradually into hypoxia are recorded using the next generation sequencing technology on the Illumina platform (RNA-seq). Gradual sampling allows identification of genes that are differentially expressed especially at the time-point when O2 starts to be limiting and whose protein products are therefore likely to play a role in O2-signalling. The original project plan has been revised to include several C. reinhardtii mutant strains deficient in the function of Crr1, a key transcriptional regulator essential for copper (Cu) and hypoxia signaling in C. reinhardtii. Very recent and yet unpublished results from both the Merchant (UCLA, USA) and Happe (RUB, Germany) groups indicate that Crr1 might play a much more important role in O2 dependent gene regulation than expected. Thus, the comparison of transcriptomes of wild type and crr1-mutant strains subjected to different O2 concentrations will allow me to gain more detailed insights into O2 signaling of C. reinhardtii. The extended project period will permit a deep analysis of sequence data by collaborating with local computational biologists.