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Human cells tolerate UV-induced cyclobutane pyrimidine dimers (CPD) by translesion DNA synthesis (TLS), carried out by DNA polymerase eta, the POLH gene product. A deficiency in DNA polymerase eta due to germ-line mutations in POLH causes the hereditary disease xeroderma pigmentosum variant (XPV), which is characterized by sunlight sensitivity and extreme(More)
DNA replication across blocking lesions occurs by translesion DNA synthesis (TLS), involving a multitude of mutagenic DNA polymerases that operate to protect the mammalian genome. Using a quantitative TLS assay, we identified three main classes of TLS in human cells: two rapid and error-free, and the third slow and error-prone. A single gene, REV3L,(More)
The encounter of replication forks with DNA lesions may lead to fork arrest and/or the formation of single-stranded gaps. A major strategy to cope with these replication irregularities is translesion DNA synthesis (TLS), in which specialized error-prone DNA polymerases bypass the blocking lesions. Recent studies suggest that TLS across a particular DNA(More)
Xeroderma pigmentosum variant (XPV) patients carry germ-line mutations in DNA polymerase eta (poleta), a major translesion DNA synthesis (TLS) polymerase, and exhibit severe sunlight sensitivity and high predisposition to skin cancer. Using a quantitative TLS assay system based on gapped plasmids we analyzed TLS across a site-specific TT CPD(More)
DNA lesions can block replication forks and lead to the formation of single-stranded gaps. These replication complications are mitigated by DNA damage tolerance mechanisms, which prevent deleterious outcomes such as cell death, genomic instability, and carcinogenesis. The two main tolerance strategies are translesion DNA synthesis (TLS), in which(More)
CTLs act as the effector arm of the cell-mediated immune system to kill undesirable cells. Two processes regulate these effector cells to prevent self reactivity: a thymic selection process that eliminates autoreactive clones and a multistage activation or priming process that endows them with a license to kill cognate target cells. Hitherto no subsequent(More)
Cells cope with replication-blocking lesions via translesion DNA synthesis (TLS). TLS is carried out by low-fidelity DNA polymerases that replicate across lesions, thereby preventing genome instability at the cost of increased point mutations. Here we perform a two-stage siRNA-based functional screen for mammalian TLS genes and identify 17 validated TLS(More)
Translesion DNA synthesis (TLS) is a DNA damage tolerance mechanism, in which specialized low-fidelity DNA polymerases bypass lesions that interfere with replication. This process is inherently mutagenic due to the miscoding nature of DNA lesions, but it prevents double strand breaks, genome instability, and cancer. We describe here a quantitative method(More)