Experimental Evolution Reveals Interplay between Sch9 and Polyploid Stability in Yeast.
Polyploidization has crucial impacts on the evolution of different eukaryotic lineages including fungi, plants and animals. Recent genome data suggest that, for many polyploidization events, all duplicated chromosomes are maintained and genome reorganizations occur much later during evolution. However, newly-formed polyploid genomes are intrinsically unstable and often quickly degenerate into aneuploidy or diploidy. The transition between these two states remains enigmatic. In this study, laboratory evolution experiments were conducted to investigate this phenomenon. We show that robust tetraploidy is achieved in evolved yeast cells by increasing the abundance of Sch9-a protein kinase activated by the TORC1 (Target of Rapamycin Complex 1) and other signaling pathways. Overexpressing SCH9, but not TOR1, allows newly-formed tetraploids to exhibit evolved phenotypes and knocking out SCH9 diminishes the evolved phenotypes. Furthermore, when cells were challenged with conditions causing ancestral cells to evolve aneuploidy, tetraploidy was maintained in the evolved lines. Our results reveal a determinant role for Sch9 during the early stage of polyploid evolution.
Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.|Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
Yi-Jin
YJ
Lu
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
Krishna B S
KB
Swamy
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
Jun-Yi
http://orcid.org/0000-0001-5445-2799
JY
Leu
D000782:Aneuploidy; D004171:Diploidy; D019020:Directed Molecular Evolution; D015966:Gene Expression Regulation, Fungal; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes / Q000096:biosynthesis / Q000235:genetics*; D011123:Polyploidy; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D058570:TOR Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics*; D057891:Tetraploidy
D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; D000076222:Mechanistic Target of Rapamycin Complex 1; D017346:Protein Serine-Threonine Kinases; C530964:SCH9 protein, S cerevisiae; D058570:TOR Serine-Threonine Kinases