Identification of transcription hubs that control lipid metabolism and carbon concentrating mechanism in model microalgae chlamydomonas reinhardtii using regulatory networks: Regulatory networks hubs in C. reinhardtii that control lipid and carbon concentrating metabolic pathways

Chlamydomonas reinhardtii is the most extensively studied eukaryotic model microalgae having essential biological pathways such as biomass production, photosynthesis, carbon concentrating mechanisms (CCMs), carbohydrate metabolism (CM), lipid metabolism (LM), and response towards nutritional stresses, with fine-tuned physiological data and genome sequence available publicly. During nitrogen (N) deprivation, C. reinhardtii accumulates oil (triacylglycerols, TAG) as storage reserves and studies to understand the entire global regulatory network is still not clear. Recent studies showed that they have identified and characterized entire set of genes encoding transcription factors (TFs) and transcriptional regulators (TRs)that control lipid metabolism relative to other genes under different stress responses using combined omics analysis but evaluation of common TFs and TRs under normal conditions involving LMand CCM in combination is essential for understanding regulatory network that may lead to identification of several regulatory hubs that controls these essential cellular processes. Our study will focus on reconstruction of a regulatory network from publicly available databases such as PlnTFDB, STRING and elucidate common TFs and TRs essential for both these mechanisms. We have identified new TFs and TRs such as, SET, PHD, FHA, Myb, Myb-related, and HMGthat play an important role in different functions such as control of chromatin and/or transcription, methylation of lysine residues, DNA repair, signal transduction etc. Also, our findings demonstrate that these TFs and TRs are involved in photoreceptor-like activities in the model microalga, which has the maximum degree of interactions with different genes and thus have relevant physiological importance in both these mechanisms.