B6.129X1-Spo11^tm1Mjn/J

Stock number: 019117
Research areas: Reproductive Biology Research

Description

Disruption of Spo11 (SPO11 meiotic protein covalently bound to DSB homolog (S. cerevisiae)) leads to severe gonadal abnormalities in both males and females due to defective meiosis.

Detailed description

Disruption of Spo11 (SPO11 meiotic protein covalently bound to DSB homolog (S. cerevisiae)) leads to severe gonadal abnormalities in both males and females due to defective meiosis.

These mice carry a targeted deletion of exons 4-6, removing a putative catalytic tyrosine encoded in exon 5. Northern blot analysis indicates that the null allele does not express transcripts.

Gonads from homozygous adult males are significantly reduced in weight. Spermatocytes undergo apoptotic death during early prophase. Oocytes from homozygous females progress to the diplotene/dictyate stage in nearly normal numbers, but most die soon after birth. Homozygotes also demonstrate defects in meiocyte homologous chromosomes and are unable to initiate meiotic recombination. Axial elements appear to be normal, but homologous synapsis is impaired.

Heterozygotes are fully fertile, but homozygous males and females are not. Homozygotes are born at predicted Mendelian ratios, indicating their viability is not affected.

Development

A targeting vector containing a neomycin resistance cassette was used to replace exons 4 to 6. The construct was electroporated into 129X1/SvJ-derived embryonic stem (ES) cells (Genome Systems). Correctly targeted ES cells were injected into C57BL/6 blastocysts. The resulting chimeric animals were crossed to C57BL/6 mice, and then backcrossed to C57BL/6J for 29 generations by the donating lab.

Allele

Symbol: Spo11^tm1Mjn
Name: targeted mutation 1, Maria Jasin
MGI accession ID: MGI:2178805
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Spo11
Marker name: SPO11 meiotic protein covalently bound to DSB
Chromosome: 2
Strain of origin: 129X1/SvJ
Molecular note: Exons 4-6 of this gene were replaced with a neomycin resistance cassette via homologous recombination thus deleting the putative catalytic tyrosine in exon 5. Northern blot assay failed to detect gene transcripts in testes of homozygous mutant males.