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Quantifying microsatellite mutation rates from intestinal stem cell dynamics in Msh2-deficient murine epithelium

Published version
Peer-reviewed

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Authors

Morrissey, Edward 
Lourenco, Filipe C 
Abujudeh, Sam 
Thorsen, Anne-Sofie 

Abstract

Microsatellite sequences have an enhanced susceptibility to mutation and can act as sentinels indicating elevated mutation rates and increased risk of cancer. The probability of mutant fixation within the intestinal epithelium is dictated by a combination of stem cell dynamics and mutation rate. Here we exploit this relationship to infer microsatellite mutation rates. First a sensitive, multiplexed and quantitative method for detecting somatic changes in microsatellite length was developed that allowed the parallel detection of mutant [CA]n sequences from hundreds of low-input tissue samples at up to 14 loci. The method was applied to colonic crypts in Mus musculus and enabled detection of mutant subclones down to 20% of the cellularity of the crypt (around 50 of 250 cells). By quantifying age-related increases in clone frequencies for multiple loci, microsatellite mutation rates in wild-type and Msh2- deficient epithelium were established. An average 388-fold increase in mutation per mitosis rate was observed in Msh2-deficient epithelium (2.4 x10-2) compared to wild- type epithelium (6.2 x10-5).

Description

Keywords

Msh2, intestine, microsatellite, mouse, mutation, Adult Stem Cells, Animals, Female, Intestinal Mucosa, Male, Mice, Mice, Inbred C57BL, Microsatellite Repeats, Mitosis, MutS Homolog 2 Protein, Mutation Rate

Journal Title

Genetics

Conference Name

Journal ISSN

0016-6731
1943-2631

Volume Title

212

Publisher

Genetics Society of America
Sponsorship
Cancer Research UK (CB4230)
Wellcome Trust (103805/Z/14/Z)