B6;129S4-Rec8^mei8/JcsMmjax

Stock number: 016587
Research areas: Reproductive Biology Research

Description

These EMS-induced mice are sterile; females exhibit ovarian dsygenesis and lack ovarian follicles. Males have small testes and lack postmeiotic spermatids. This mutant mouse strain may be useful in studies of meiosis, synaptonemal complex assembly, double strand break repair and sister chromatid cohesion.

Detailed description

Homozygotes: Mice that are homozygous for this chemically induced mutation are sterile. Females exhibit ovarian dsygenesis and lack ovarian follicles at reproductive maturity. Testes in affected males are about 50% smaller than wild-type at 5-6 weeks of age due to arrest of spermatogenesis during meiotic prophase I. No postmeiotic spermatids are observed in the seminiferous tubules of 5 week old mice. The underlying cause for arrest in both sexes is failure to repair Spo11-induced meiotic double strand breaks, plus improper synapsis.This mutant mouse strain may be useful in studies of meiosis, synaptonemal complex assembly, double strand break repair and sister chromatid cohesion.

Heterozygote: Heterozygote phenotype is expected to be similar to wildtype phenotype.

Development

The mei8 mutation was induced in (C57BL/6J x 129S4/SvJae)F1 derived v6.4 ES cells via exposure to ethyl methansulfonate (EMS)during a forward genetic screen for infertility mutations. EMS exposure resulted in a C to T transversion in the terminal amino acid of exon 6 of the Rec8 gene. The mutation alters the corresponding amino acid from cysteine to threonine creating a premature translational stop at amino acid 155 (C155T) and eliminating exons 7 through 20. The donating investigator reported that chimeric males were mated to C57BL/6J females and offspring were backcrossed to C57BL/6J for 9 generations (see SNP note below). Males donated to the MMRRC were cryopreserved by sperm.

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. 3 of the 27 markers were segregating for 129 suggesting an incomplete backcross.

Allele

Symbol: Rec8^mei8
Name: mei8, John Schimenti
MGI accession ID: MGI:3512754
Generation method: Chemically induced (other)
Attributes: Null/Knockout
Marker symbol: Rec8
Marker name: REC8 meiotic recombination protein
Chromosome: 14
Strain of origin: (C57BL/6J x 129S4/SvJae)F1
Molecular note: ES cells were mutagenized using ethyl methansulfonate (EMS). The allele has a C to T nonsense mutation at bp 46,747,592 of the Ensembl mouse genome assembly, NCBI build m32. The surrounding sequence encodes the terminal amino acid of exon 6, and the mutation created a premature translational stop at amino acid 155 of 591, thereby eliminating exons 7 through 20. RT-PCR of testes samples from mutants confirmed the lack of transcript.