Regulation of Saccharomyces cerevisiae DNA polymerase η transcript and protein

• Published in: Radiation and environmental biophysics Vol. 47; no. 1; pp. 157 - 168
• Main Authors: Pabla, Ritu, Rozario, Donald, Siede, Wolfram
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2008
• Subjects: Amino Acid Motifs; Biological and Medical Physics; Biophysics; DNA Damage - radiation effects; DNA Repair - physiology; DNA Repair - radiation effects; DNA Replication - physiology; DNA Replication - radiation effects; DNA-Directed DNA Polymerase - biosynthesis; DNA-Directed DNA Polymerase - radiation effects; Ecosystems; Effects of Radiation/Radiation Protection; Environmental Physics; Enzyme Activators; Genes, Fungal - radiation effects; Monitoring/Environmental Analysis; Original Paper; Physics; Physics and Astronomy; RNA, Fungal - analysis; RNA, Fungal - radiation effects; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - radiation effects; Saccharomyces cerevisiae Proteins - biosynthesis; Saccharomyces cerevisiae Proteins - radiation effects; Ubiquitin-Conjugating Enzymes - genetics; Ubiquitin-Conjugating Enzymes - radiation effects; Ubiquitination - physiology; Ultraviolet Rays - adverse effects; Ubiquitinated Substrate; Proliferate Cell Nuclear Antigen; Rad30 Protein; Haploid Cell; Cell Cycle Stage
• ISSN: 0301-634X; 1432-2099
• DOI: 10.1007/s00411-007-0132-1

RAD30 -encoded DNA polymerase η functions as a translesion polymerase that can bypass the most frequent types of UV-induced pyrimidine photoproducts in an error-free manner. Although its transcript is UV-inducible in Saccharomyces cerevisiae , Rad30 (studied as a Rad30-Myc fusion) is a stable protein whose levels do not fluctuate following UV treatment or during cell cycle progression. Rad30 protein is subject to monoubiquitination whose level is upregulated in G1 and downregulated during S-phase reentry. This downregulation is accelerated in UV-treated cells. A missense mutation (L577Q) of the ubiquitin binding domain (UBZ) confers a reduced degree of ubiquitination outside of G1 and a complete failure to stably interact with ubiquitinated substrates. This mutation confers a phenotype resembling a complete RAD30 deletion, thus attesting to the significance of the UBZ motif for polymerase η function in vivo.