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.
