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Involvement of mouse Mlh1 in DNA mismatch repair and meiotic crossing over

S M Baker1, A W Plug, T A Prolla

  • 1Department of Molecular and Medical Genetics, Oregon Health Sciences University, Portland 97201-3098, USA.

Nature Genetics
|July 1, 1996
PubMed

Insights

Mice lacking the Mlh1 DNA repair gene show DNA instability and infertility in both sexes. Mlh1 deficiency also causes meiotic errors, suggesting its role in DNA repair and chromosome pairing.

Area of Science:

  • Genetics and Molecular Biology
  • Reproductive Biology
  • Cancer Biology

Background:

  • DNA mismatch repair (MMR) genes, such as Pms2 and Msh2, are crucial for genomic stability.
  • Deficiency in MMR genes leads to microsatellite instability and increased tumor susceptibility.
  • Previous studies noted sterility in Pms2-deficient male mice linked to meiotic abnormalities.

Purpose of the Study:

  • To investigate the role of the Mlh1 gene, another MMR gene, in DNA repair and meiosis.
  • To determine the reproductive and chromosomal consequences of Mlh1 deficiency in mice.

Main Methods:

  • Generation and analysis of Mlh1-deficient mice.
  • Assessment of microsatellite instability.
  • Examination of meiotic progression and chromosome pairing in spermatocytes.
  • Localization studies of Mlh1 protein on meiotic chromosomes.

Main Results:

  • Mlh1-deficient mice exhibited microsatellite instability and infertility in both males and females.
  • Mlh1-deficient spermatocytes displayed premature chromosome separation and meiotic arrest.
  • Mlh1 was observed at sites of crossing over during meiosis.

Conclusions:

  • Mlh1 plays a significant role in both DNA mismatch repair and meiotic crossing over.
  • Mlh1 deficiency disrupts normal meiosis, leading to infertility.
  • These findings highlight the dual function of Mlh1 in maintaining genomic integrity and ensuring successful reproduction.

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