In yeast, Rad6-Rad18-dependent lesion bypass involves translesion synthesis (TLS) by DNA polymerases eta or zeta or Rad5-dependent postreplication repair (PRR) in which error-free replication through the DNA lesion occurs by template switching. Rad5 functions in PRR via its two distinct activities--a ubiquitin ligase that promotes Mms2-Ubc13-mediated K63-linked polyubiquitination of PCNA at its lysine 164 residue and a DNA helicase that is specialized for replication fork regression. Both these activities are important for Rad5's ability to function in PRR. Here we provide evidence for the requirement of Rad5 in TLS mediated by Polzeta. Using duplex plasmids carrying different site-specific DNA lesions--an abasic site, a cis-syn TT dimer, a (6-4) TT photoproduct, or a G-AAF adduct--we show that Rad5 is needed for Polzeta-dependent TLS. Rad5 action in this role is likely to be structural, since neither the inactivation of its ubiquitin ligase activity nor the inactivation of its helicase activity impairs its role in TLS.
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http://dx.doi.org/10.1534/genetics.108.091066 | DOI Listing |
J Biol Chem
January 2025
Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The province and ministry co-sponsored collaborative innovation center for medical epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Tianjin Medical University, 300070 Tianjin, P. R. CHINA. Electronic address:
Ubiquitination of the proliferating cell nuclear antigen (PCNA) by the budding yeast protein Rad5 have important functions in replication stress responses. Rad5 together with the Ubc13-Mms2 complex attaches Lys63-linked ubiquitin chain to a highly conserved Lys164 residue in PCNA. The reaction requires prior PCNA mono-ubiquitination by the Rad6-Rad18 complex and signals for error-free DNA damage tolerance responses.
View Article and Find Full Text PDFSpine J
November 2024
Department of Diagnostic Imaging, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore; Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
Background Context: Secure institutional large language models (LLM) could reduce the burden of noninterpretative tasks for radiologists.
Purpose: Assess the utility of a secure institutional LLM for MRI spine request form enhancement and auto-protocoling.
Study Design/setting: Retrospective study conducted from December 2023 to February 2024, including patients with clinical entries accessible on the electronic medical record (EMR).
EBioMedicine
February 2024
University of Pennsylvania, Philadelphia, PA, USA.
Background: Elicitation of broad immune responses is understood to be required for an efficacious preventative HIV vaccine. This Phase 1 randomized controlled trial evaluated whether administration of vaccine antigens separated at multiple injection sites vs combined, fractional delivery at multiple sites affected T-cell breadth compared to standard, single site vaccination.
Methods: We randomized 90 participants to receive recombinant adenovirus 5 (rAd5) vector with HIV inserts gag, pol and env via three different strategies.
Genetics
November 2023
Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
Upon DNA replication stress, cells utilize the postreplication repair pathway to repair single-stranded DNA and maintain genome integrity. Postreplication repair is divided into 2 branches: error-prone translesion synthesis, signaled by proliferating cell nuclear antigen (PCNA) monoubiquitination, and error-free template switching, signaled by PCNA polyubiquitination. In Saccharomyces cerevisiae, Rad5 is involved in both branches of repair during DNA replication stress.
View Article and Find Full Text PDFmBio
April 2023
Beijing Key Laboratory of DNA Damage Responses and College of Life Sciences, Capital Normal University, Beijing, China.
DNA-damage tolerance (DDT) is a mechanism by which eukaryotes bypass replication-blocking lesions to resume DNA synthesis and maintain cell viability. In Saccharomyces cerevisiae, DDT is mediated by sequential ubiquitination and sumoylation of proliferating cell nuclear antigen (PCNA, encoded by ) at the K164 residue. Deletion of or , encoding two ubiquitin ligases required for PCNA ubiquitination, results in severe DNA-damage sensitivity, which can be rescued by inactivation of encoding a DNA helicase that inhibits undesired homologous recombination.
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