Identification of a novel deletion mutant strain in Saccharomyces cerevisiae that results in a microsatellite instability phenotype

By

Ji, Hanlee
Morales, Shannon
Welch, Katrina
Yuen, Cam
Farnam, Kyle
Ford, James

Type

Article

Date of Publication

2012-7-23

Original Publication

Nature conservation

Volume

1

Pages

1--9

Subjects

microarray , microsatellite instability , Saccharomyces cerevisiae , Yeast

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers 2012-

Identifiers

DOI: https://doi.org/10.7750/BioDiscovery.2012.1.4

 

Abstract

The DNA mismatch repair (MMR) pathway corrects specific types of DNA replication errors that affect microsatellites and thus is critical for maintaining genomic integrity. The genes of the MMR pathway are highly conserved across different organisms. Likewise, defective MMR function universally results in microsatellite instability (MSI) which is a hallmark of certain types of cancer associated with the Mendelian disorder hereditary nonpolyposis colorectal cancer. (Lynch syndrome). To identify previously unrecognized deleted genes or loci that can lead to MSI, we developed a functional genomics screen utilizing a plasmid containing a microsatellite sequence that is a host spot for MSI mutations and the comprehensive homozygous diploid deletion mutant resource for Saccharomyces cerevisiae. This pool represents a collection of non-essential homozygous yeast diploid (2N) mutants in which there are deletions for over four thousand yeast open reading frames (ORFs). From this screen, we identified a deletion mutant strain of the <i>PAU24</i> gene that leads to MSI. In a series of validation experiments, we determined that this <i>PAU24</i> mutant strain had an increased MSI-specific mutation rate in comparison to the original background wildtype strain, other deletion mutants and comparable to a MMR mutant involving the MLH1 gene. Likewise, in yeast strains with a deletion of <i>PAU24</i>, we identified specific de novo indel mutations that occurred within the targeted microsatellite used for this screen.