Related Experiment Video
Updated: Mar 27, 2026
Medium-throughput Screening Assays for Assessment of Effects on Ca2+-Signaling and Acrosome Reaction in Human Sperm
Published on: March 1, 2019
An intact Pms2 ATPase domain is not essential for male fertility
Jared M Fischer1, Sandra Dudley1, Ashleigh J Miller1
1Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR 97239, USA.
Abstract:
The DNA mismatch repair (MMR) machinery in mammals plays critical roles in both mutation avoidance and spermatogenesis. Meiotic analysis of knockout mice of two different MMR genes, Mlh1 and Mlh3, revealed both male and female infertility associated with a defect in meiotic crossing over. In contrast, another MMR gene knockout, Pms2 (Pms2(ko/ko)), which contained a deletion of a portion of the ATPase domain, produced animals that were male sterile but female fertile. However, the meiotic phenotype of Pms2(ko/ko) males was less clear-cut than for Mlh1- or Mlh3-deficient meiosis. More recently, we generated a different Pms2 mutant allele (Pms2(cre)), which results in deletion of the same portion of the ATPase domain. Surprisingly, Pms2(cre/cre) male mice were completely fertile, suggesting that the ATPase domain of Pms2 is not required for male fertility. To explore the difference in male fertility, we examined the Pms2 RNA and found that alternative splicing of the Pms2(cre) allele results in a predicted Pms2 containing the C-terminus, which contains the Mlh1-interaction domain, a possible candidate for stabilizing Mlh1 levels. To study further the basis of male fertility, we examined Mlh1 levels in testes and found that whereas Pms2 loss in Pms2(ko/ko) mice results in severely reduced levels of Mlh1 expression in the testes, Mlh1 levels in Pms2(cre/cre) testes were reduced to a lesser extent. Thus, we propose that a primary function of Pms2 during spermatogenesis is to stabilize Mlh1 levels prior to its critical crossing over function with Mlh3.
Insights
The DNA mismatch repair gene Pms2 stabilizes Mlh1 levels in male mice, which is crucial for fertility and proper meiotic crossing over during spermatogenesis.
Area of Science:
- Molecular Biology
- Genetics
- Reproductive Biology
Background:
- The DNA mismatch repair (MMR) system is essential for maintaining genomic stability and plays a vital role in mammalian spermatogenesis.
- Previous studies showed MMR gene deficiencies (Mlh1, Mlh3) cause infertility due to defective meiotic crossing over.
- A Pms2 knockout (Pms2(ko/ko)) resulted in male sterility, but the underlying meiotic defect was unclear.
Purpose of the Study:
- To investigate the role of the Pms2 ATPase domain in male fertility and spermatogenesis.
- To elucidate the molecular mechanisms underlying the differential male fertility observed in distinct Pms2 mutant alleles.
- To determine the relationship between Pms2, Mlh1 levels, and meiotic crossing over in male mice.
Main Methods:
- Generation and analysis of a new Pms2 mutant allele (Pms2(cre)) with a deletion in the ATPase domain.
- Meiotic analysis and fertility assessment of Pms2(cre/cre) and Pms2(ko/ko) mutant mice.
- Quantitative analysis of Pms2 RNA splicing and Mlh1 protein levels in mouse testes.
Main Results:
- Pms2(cre/cre) male mice, unlike Pms2(ko/ko) mice, were completely fertile, indicating the ATPase domain is not essential for male fertility.
- Alternative splicing in the Pms2(cre) allele preserves the Mlh1-interaction domain, potentially stabilizing Mlh1.
- Pms2(ko/ko) testes showed severely reduced Mlh1 levels, while Pms2(cre/cre) testes had moderately reduced Mlh1 levels compared to wild-type.
Conclusions:
- The Pms2 ATPase domain is dispensable for male fertility.
- Pms2's primary function in spermatogenesis is to stabilize Mlh1 levels, likely via its C-terminal Mlh1-interaction domain.
- Adequate Mlh1 levels, stabilized by Pms2, are critical for successful meiotic crossing over and male fertility.
Related Concept Videos
02:19The Y Chromosome Determines Maleness
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size....
01:23Infertility in Males
02:26Conservation of Protein Domains Over Different Proteins
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to...
01:41Spermatogenesis
01:22Spermatogenesis
The process of spermatogenesis can be divided into mitosis, meiosis, and spermiogenesis. During mitosis, the spermatogonia or stem cells divide to produce two identical daughter cells, type A and B spermatogonia. Type-A...
01:48ATP Synthase: Mechanism