Related Experiment Video

Updated: Jun 18, 2026

Preparation of Meiotic Chromosome Spreads from Mouse Oocytes for Assessment of Synapsis and Recombination
09:24

Preparation of Meiotic Chromosome Spreads from Mouse Oocytes for Assessment of Synapsis and Recombination

Published on: July 18, 2025

Regulation of meiotic recombination via Mek1-mediated Rad54 phosphorylation

Hengyao Niu1, Lihong Wan, Valeria Busygina

  • 1Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA.

Molecular Cell
|November 18, 2009
PubMed

Insights

Meiosis uses Mek1 kinase to control DNA recombination by inhibiting Rad51 recombinase activity. This ensures homologs are preferred over sister chromatids, preventing errors during cell division.

Area of Science:

  • Molecular Biology
  • Genetics
  • Cell Biology

Background:

  • Homologous recombination (HR) differs between meiosis and mitosis.
  • Meiosis favors interhomolog recombination, while mitosis favors sister chromatid engagement.
  • In budding yeast, Dmc1 and Mek1 are crucial for meiotic interhomolog bias, with Mek1 suppressing Rad51 on sister chromatids.

Purpose of the Study:

  • To investigate the additional roles of Mek1 in controlling recombination partner choice during meiosis.
  • To elucidate the mechanism by which Mek1 regulates the activity of the Rad51 recombinase.

Main Methods:

  • Proteomic analysis
  • Biochemical assays
  • Genetic approaches

Main Results:

  • Mek1 inhibits Rad51 activity by phosphorylating its partner, Rad54, at threonine 132.
  • Phosphorylation at threonine 132 attenuates Rad51/Rad54 complex formation.
  • This phosphorylation reduces Rad51 function both in vitro and in vivo.
  • Mek1 also suppresses sister chromatid invasion independently of Rad54.

Conclusions:

  • Mek1 phosphorylation of Rad54 is a key mechanism controlling recombination partner choice in meiosis.
  • This regulation ensures accurate chromosome segregation by favoring homologs over sister chromatids.
  • Mek1 employs dual mechanisms, involving Rad54 and a Rad54-independent pathway, to control Rad51 activity.

More Related Videos

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad5106:24

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51

Published on: February 13, 2019

Visualization of DNA Repair Proteins Interaction by Immunofluorescence07:55

Visualization of DNA Repair Proteins Interaction by Immunofluorescence

Published on: June 26, 2020

Related Concept Videos

Restarting Stalled Replication Forks02:37

Restarting Stalled Replication Forks

DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
Conservative Site-specific Recombination and Phase Variation02:53

Conservative Site-specific Recombination and Phase Variation

Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
Crossing Over01:30

Crossing Over

Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I, duplicated...
Homologous Recombination02:31

Homologous Recombination

The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
DNA Damage can Stall the Cell Cycle02:36

DNA Damage can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...