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Spontaneous Irs1 passenger mutation linked to a gene-targeted SerpinB2 allele.

Abstract：

:In characterizing mice with targeted disruption of the SerpinB2 gene, we observed animals that were small at birth with delayed growth and decreased life expectancy. Although this phenotype cosegregated with homozygosity for the inactive SerpinB2 allele, analysis of homozygous SerpinB2-deficient mice derived from two additional independent embryonic stem (ES) cell clones exhibited no growth abnormalities. Examination of additional progeny from the original SerpinB2-deficient line revealed recombination between the small phenotype (smla) and the SerpinB2 locus. The locus responsible for smla was mapped to a 2.78-Mb interval approximately 30 Mb proximal to SerpinB2, bounded by markers D1Mit382 and D1Mit216. Sequencing of Irs1 identified a nonsense mutation at serine 57 (S57X), resulting in complete loss of IRS1 protein expression. Analysis of ES cell DNA suggests that the S57X Irs1 mutation arose spontaneously in an ES cell subclone during cell culture. Although the smla phenotype is similar to previously reported Irs1 alleles, mice exhibited decreased survival, in contrast to the enhanced longevity reported for IRS1 deficiency generated by gene targeting. This discrepancy could result from differences in strain background, unintended indirect effects of the gene targeting, or the minimal genetic interference of the S57X mutation compared with the conventionally targeted Irs1-KO allele. Spontaneous mutations arising during ES cell culture may be a frequent but underappreciated occurrence. When linked to a targeted allele, such mutations could lead to incorrect assignment of phenotype and may account for a subset of markedly discordant results from experiments independently targeting the same gene.

journal_name

Proc Natl Acad Sci U S A

journal_title

Proceedings of the National Academy of Sciences of the United States of America

authors

Westrick RJ,Mohlke KL,Korepta LM,Yang AY,Zhu G,Manning SL,Winn ME,Dougherty KM,Ginsburg D

doi

10.1073/pnas.1012050107

subject

Has Abstract

pub_date

2010-09-28 00:00:00

pages

16904-9

issue

eissn

0027-8424

issn

1091-6490

pii

1012050107

journal_volume

107

pub_type

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Spontaneous Irs1 passenger mutation linked to a gene-targeted SerpinB2 allele.