کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2147590 1548419 2006 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The role of DNA polymerase ι in UV mutational spectra
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی تحقیقات سرطان
پیش نمایش صفحه اول مقاله
The role of DNA polymerase ι in UV mutational spectra
چکیده انگلیسی

UVB (280–320 nm) and UVC (200–280 nm) irradiation generate predominantly cyclobutane pyrimidine dimers (CPDs) and (6-4) photoproducts in DNA. CPDs are thought to be responsible for most of the UV-induced mutations. Thymine–thymine CPDs, and probably also CPDs containing cytosine, are replicated in vivo in a largely accurate manner by a DNA polymerase η (Pol η) dependent process. Pol η is a DNA damage-tolerant and error-prone DNA polymerase encoded by the POLH (XPV) gene in humans. Another member of the Y family of error-prone DNA polymerases is POLI encoding DNA polymerase iota (Pol ι). In order to clarify the specific role of Pol ι in UV mutagenesis, we have used an siRNA knockdown approach in combination with a supF shuttle vector which replicates in mammalian cells, similar as we have previously done for Pol η. Synthetic RNA duplexes were used to efficiently inhibit Pol ι expression in 293T cells. The supF shuttle vector was irradiated with 254 nm UVC and replicated in 293T cells in presence of anti-Pol ι siRNA. Surprisingly, there was a consistent reduction of recovered plasmid from cells with Pol ι knockdown and this was independent of UV irradiation of the plasmid. The supF mutant frequency was unchanged in the siRNA knockdown cells relative to control cells confirming that Pol ι does not play an important role in UV mutagenesis. UV-induced supF mutants were sequenced from siRNA-treated cells and controls. Neither the type of mutations nor their distribution along the supF gene were significantly different between controls and siRNA knockdown cells and were predominantly C to T and CC to TT transitions at dipyrimidine sites. These results show that Pol ι has no significant role in UV lesion bypass and mutagenesis in vivo and provides some initial data suggesting that this polymerase may be involved in replication of extrachromosomal DNA.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis - Volume 599, Issues 1–2, 25 July 2006, Pages 58–65
نویسندگان
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