S-Adenosylmethionine Synthetase Is Required for Cell Growth, Maintenance of G0 Phase, and Termination of Quiescence in Fission Yeast

Takeshi Hayashi; Takayuki Teruya; Romanas Chaleckis; Susumu Morigasaki; Mitsuhiro Yanagida

doi:10.1016/j.isci.2018.06.011

S-Adenosylmethionine Synthetase Is Required for Cell Growth, Maintenance of G0 Phase, and Termination of Quiescence in Fission Yeast

iScience. 2018 Jul 27:5:38-51. doi: 10.1016/j.isci.2018.06.011. Epub 2018 Jun 30.

Authors

Takeshi Hayashi¹, Takayuki Teruya¹, Romanas Chaleckis¹, Susumu Morigasaki¹, Mitsuhiro Yanagida²

Affiliations

¹ G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan.
² G0 Cell Unit, Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan. Electronic address: myanagid@gmail.com.

Abstract

S-adenosylmethionine is an important compound, because it serves as the methyl donor in most methyl transfer reactions, including methylation of proteins, nucleic acids, and lipids. However, cellular defects in the genetic disruption of S-adenosylmethionine synthesis are not well understood. Here, we report the isolation and characterization of temperature-sensitive mutants of fission yeast S-adenosylmethionine synthetase (Sam1). Levels of S-adenosylmethionine and methylated histone H3 were greatly diminished in sam1 mutants. sam1 mutants stopped proliferating in vegetative culture and arrested specifically in G2 phase without cell elongation. Furthermore, sam1 mutants lost viability during nitrogen starvation-induced G0 phase quiescence. After release from the G0 state, sam1 mutants could neither increase in cell size nor re-initiate DNA replication in the rich medium. Sam1 is thus required for cell growth and proliferation, and maintenance of and exit from quiescence. sam1 mutants lead to broad cellular and drug response defects, as expected, since S. pombe contains more than 90 S-adenosylmethionine-dependent methyltransferases.

Keywords: Cell Biology; Functional Aspects of Cell Biology; Model Organism; Molecular Mechanism of Behavior.