[PhD Thesis Presentation] - Caroline Starzynski
Title: Investigating an evolutionarily conserved metabolic mechanism contributing to G0 quiescence survival in S. pombe
Speaker: Caroline, Starzynski
Affiliation: PhD Student - G0 Cell Unit (Yanagida Unit)
Abstract: Since all living organism rely on assimilating environmental nitrogen (N) to promote cell division, an efficient system to deal with N scarcity is deterministic for survival. For example, the fission yeast Schizosaccharomyces pombe (S. pombe) withstands long-term N starvation by induction of division arrest and quiescence entry (G0 phase). In past studies 89 S. pombe genes were found to be required for G0 phase transition. Because these are involved in diverse intracellular functions, a coherent mechanism for quiescence was difficult to assign. Therefore, we developed a BLAST-based approach to characterize evolutionary conserved core metabolic functions by comparative analysis using prokaryotic databases of Escherichia coli and Bacillus subtilis. We report thirteen proteins fulfilling this study’s homology criteria, the majority of which (8/13) are localized to the mitochondria. Subsequent in silico analysis suggests the involvement of two functional response mechanisms which comprise oxygen-associated (Sod2, Nde1, Coq5, Ilv3) and glutamate metabolic (Gdh1, Maa1, Lys12, Ilv3) reactions. Among these, ∆sod2 and ∆coq5 mutants showed abnormal oxygen consumption upon quiescence. Similarly, ∆ilv3 was affected in respiration which suggests its functional link to both responses. We report that the conserved core mechanisms to survive N starvation comprise enzymes which are associated with the regulation of oxygen and glutamate metabolism.