Regulation of Saccharomyces cerevisiae DNA polymerase η transcript and protein
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- Pabla, R., Rozario, D. & Siede, W. Radiat Environ Biophys (2008) 47: 157. doi:10.1007/s00411-007-0132-1
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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.