title: The steady-state level and stability of TLS polymerase eta are cell cycle dependent in the yeast S. cerevisiae.
abstract: Polymerase eta (Pol eta) is a ubiquitous translesion DNA polymerase that is capable of bypassing UV-induced pyrimidine dimers in an error-free manner. However, this specialized polymerase is error prone when synthesizing through an undamaged DNA template. In Saccharomyces cerevisiae, both depletion and overproduction of Pol eta result in mutator phenotypes. Therefore, regulation of the cellular abundance of this enzyme is of particular interest. However, based on the investigation of variously tagged forms of Pol eta, mutually contradictory conclusions have been reached regarding the stability of this polymerase in yeast. Here, we optimized a protocol for the detection of untagged yeast Pol eta and established that the half-life of the native enzyme is 80 ± 14 min in asynchronously growing cultures. Experiments with synchronized cells indicated that the cellular abundance of this translesion polymerase changes throughout the cell cycle. Accordingly, we show that the stability of Pol eta, but not its mRNA level, is cell cycle stage dependent. The half-life of the polymerase is more than fourfold shorter in G1-arrested cells than in those at G2/M. Our results, in concert with previous data for Rev1, indicate that cell cycle regulation is a general property of Y family TLS polymerases in S. cerevisiae.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Plachta
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Halas
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: McIntyre
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland. Electronic address: esg@ibb.waw.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Sledziewska-Gojska
mesh_terms: D002453:Cell Cycle; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D006207:Half-Life; D055550:Protein Stability; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D000099270:Y-Family DNA Polymerases
chemical_list: D004259:DNA-Directed DNA Polymerase; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases
keywords: Cell cycle; Polymerase eta; S. cerevisiae; TLS; Y family polymerases