title: Polymerase eta is a short-lived, proteasomally degraded protein that is temporarily stabilized following UV irradiation in Saccharomyces cerevisiae.
abstract: Saccharomyces cerevisiae Rad30 is the homolog of human DNA polymerase eta whose inactivation leads to the cancer-prone syndrome xeroderma pigmentosum variant. Both human and yeast polymerase eta are responsible for error-free bypass of UV-induced cis-syn pyrimidine dimers and several other DNA lesions. Here we show, using yeast strains expressing TAP-tagged Rad30, that the level of this protein is post-translationally regulated via ubiquitination and proteasome-mediated degradation. The half-life of Rad30 is 20 min and it increases due to proteasomal defects. Mutations inactivating components of the Skp1/cullin/ F-box (SCF) ubiquitin ligase complex: Skp1 and the F-box protein Ufo1 stabilize Rad30. Our results indicate also that ultraviolet irradiation causes transient stabilization of Rad30, which leads, in turn, to temporary accumulation of this polymerase in the cell. We conclude that proteolysis plays an important role in regulating the cellular abundance of Rad30. These results are the first indication of a role for controlled proteasomal degradation in modulating cellular level of translesion DNA polymerase in eukaryotes.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Adrianna
authors.initials: A
authors.lastname: Skoneczna
authors.forename: Justyna
authors.initials: J
authors.lastname: McIntyre
authors.forename: Marek
authors.initials: M
authors.lastname: Skoneczny
authors.forename: Zofia
authors.initials: Z
authors.lastname: Policinska
authors.forename: Ewa
authors.initials: E
authors.lastname: Sledziewska-Gojska
mesh_terms: D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D004795:Enzyme Stability; D015971:Gene Expression Regulation, Enzymologic; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism* / Q000502:physiology / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014466:Ultraviolet Rays; D000099270:Y-Family DNA Polymerases
chemical_list: D004259:DNA-Directed DNA Polymerase; D046988:Proteasome Endopeptidase Complex; D029701:Saccharomyces cerevisiae Proteins; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases