Related Experiment Video

Updated: May 7, 2026

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy
11:40

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy

Published on: June 25, 2013

11.4K

Mph1 and Mus81-Mms4 prevent aberrant processing of mitotic recombination intermediates

Gerard Mazón1, Lorraine S Symington

  • 1Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA.

Molecular Cell
|October 15, 2013
PubMed

Insights

The Saccharomyces cerevisiae Mph1 helicase prevents genome rearrangements by removing DNA repair intermediates. Loss of Mph1 or nucleases impairs double-strand break repair, leading to problematic joint molecule accumulation.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Homology-dependent repair of double-strand breaks (DSBs) can lead to loss of heterozygosity and genome rearrangements.
  • Ectopic recombination poses a risk for genomic instability.

Purpose of the Study:

  • To investigate the role of Saccharomyces cerevisiae Mph1 helicase in preventing crossovers between ectopic sequences.
  • To elucidate the roles of nucleases Mus81-Mms4, Rad1-Rad10, and Yen1 in DSB repair pathways.

Main Methods:

  • Genetic analysis of Saccharomyces cerevisiae mutants lacking key DNA repair proteins (Mph1, Mus81-Mms4, Rad1-Rad10, Yen1).
  • Observation of DNA repair intermediates, including joint molecules (JMs) and Holliday junctions (HJs).

Main Results:

  • Mph1 prevents crossovers by removing substrates for Mus81-Mms4 and Rad1-Rad10 cleavage.
  • Cells lacking Mph1 and the three nucleases exhibit severe defects in DSB repair.
  • Ectopic JMs accumulate in mph1Δ and mus81Δ mutants, with mus81Δ JMs containing single HJs, hindering processing by the Sgs1-Top3-Rmi1 complex (STR).

Conclusions:

  • Mph1 and Mus81-Mms4 likely recognize early strand exchange intermediates in DSB repair.
  • These proteins direct repair towards noncrossover or crossover outcomes, respectively.
  • The study highlights the coordinated action of helicases and nucleases in maintaining genome stability during DSB repair.

More Related Videos

Preparation of Meiotic Chromosome Spreads from Mouse Oocytes for Assessment of Synapsis and Recombination09:24

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

Published on: July 18, 2025

1.2K
Analysis of Somatic Hypermutation in the JH4 intron of Germinal Center B cells from Mouse Peyer's Patches09:35

Analysis of Somatic Hypermutation in the JH4 intron of Germinal Center B cells from Mouse Peyer's Patches

Published on: April 20, 2021

7.5K

Related Concept Videos

Mismatch Repair01:20

Mismatch Repair

Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
5.4K
Mismatch Repair01:36

Mismatch Repair

Overview
38.2K
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the...
4.0K
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...
5.7K
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,...
5.1K
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...
59.0K