Synaptonemal complex length variation in wild-type male mice.

Area of Science:

• Genetics
• Cell Biology
• Reproductive Biology

Background:

• Meiosis produces haploid gametes through two cell divisions without DNA replication.
• The synaptonemal complex (SC) is crucial for homologous chromosome segregation during Meiosis I.

Purpose of the Study:

• To measure and compare total average autosomal SC lengths in mouse spermatocytes.
• To investigate the genetic basis for observed differences in SC length.
• To explore the role of specific genes in SC length regulation.

Main Methods:

• Quantification of total autosomal SC lengths in spermatocytes from 129S4/SvJae, C57BL/6J, and BALB/c mouse strains.
• Analysis of SC lengths in F1 hybrid mice.
• Gene expression analysis of selected genes involved in meiotic chromosome architecture, focusing on REC8 mRNA and protein levels.

Main Results:

• BALB/c spermatocytes showed a 9% shorter total autosomal SC length compared to 129S4/SvJae and C57BL/6J strains.
• Shorter SCs were also observed in F1 hybrids, suggesting a genetic influence on SC length.
• BALB/c testes displayed significantly lower REC8 mRNA (up to 6-fold) and REC8 protein (up to 4-fold) expression.

Conclusions:

• SC length regulation in mice is influenced by genetic background.
• Reduced REC8 expression is associated with shorter SC lengths, indicating a REC8-dependent mechanism.
• Variations in genetic background can affect outcomes in mouse meiotic studies.