کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2147654 1548423 2006 18 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Replication restart: A pathway for (CTG)·(CAG) repeat deletion in Escherichia coli
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی تحقیقات سرطان
پیش نمایش صفحه اول مقاله
Replication restart: A pathway for (CTG)·(CAG) repeat deletion in Escherichia coli
چکیده انگلیسی

(CTG)n·(CAG)n repeats undergo deletion at a high rate in plasmids in Escherichia coli in a process that involves RecA and RecB. In addition, DNA replication fork progression can be blocked during synthesis of (CTG)n·(CAG)n repeats. Replication forks stalled at (CTG)n·(CAG)n repeats may be rescued by replication restart that involves recombination as well as enzymes involved in replication and DNA repair, and this process may be responsible for the high rate of repeat deletion in E. coli. To test this hypothesis (CAG)n·(CTG)n deletion rates were measured in several E. coli strains carrying mutations involved in replication restart. (CAG)n·(CTG)n deletion rates were decreased, relative to the rates in wild type cells, in strains containing mutations in priA, recG, ruvAB, and recO. Mutations in priB and priC resulted in small reductions in deletion rates. In a recF strain, rates were decreased when (CAG)n comprised the leading template strand, but rates were increased when (CTG)n comprised the leading template. Deletion rates were increased slightly in a recJ strain. The mutational spectra for most mutant strains were altered relative to those in parental strains. In addition, purified PriA and RecG proteins showed unexpected binding to single-stranded, duplex, and forked DNAs containing (CAG)n and/or (CTG)n loop-outs in various positions. The results presented are consistent with an interpretation that the high rates of trinucleotide repeat instability observed in E. coli result from the attempted restart of replication forks stalled at (CAG)n·(CTG)n repeats.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis - Volume 595, Issues 1–2, 20 March 2006, Pages 5–22
نویسندگان
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