Related Experiment Video

Updated: Aug 17, 2026

Visualization of DNA Repair Proteins Interaction by Immunofluorescence
07:55

Visualization of DNA Repair Proteins Interaction by Immunofluorescence

Published on: June 26, 2020

Srs2 and Sgs1 DNA helicases associate with Mre11 in different subcomplexes following checkpoint activation and

Irene Chiolo1, Walter Carotenuto, Giulio Maffioletti

  • 1FIRC Institute of Molecular Oncology Foundation, Via Adamello 16, 20139, Milan, Italy.

Molecular and Cellular Biology
|June 21, 2005
PubMed

Insights

DNA repair proteins Srs2, Sgs1, and Mre11 form a complex that reorganizes upon DNA damage. Checkpoint kinases Mec1 and Tel1 regulate these interactions, highlighting Srs2 as a target in DNA damage response.

Area of Science:

  • Molecular Biology
  • Genetics
  • Cell Biology

Background:

  • Mutations in BLM, WRN, and the MRE11-RAD50-NBS1 complex cause genome instability and cancer.
  • Saccharomyces cerevisiae Sgs1 (a RecQ helicase), Mre11, and Srs2 (a DNA helicase) prevent chromosome rearrangements and are involved in DNA damage response and recombination.

Purpose of the Study:

  • To identify physical interactors of the Srs2 DNA helicase.
  • To elucidate the functional interactions between Srs2, Sgs1, and Mre11 in DNA repair and checkpoint pathways.

Main Methods:

  • Yeast two-hybrid screening to identify Srs2 interactors.
  • Co-immunoprecipitation to confirm complex formation.
  • Analysis of mutant strains (mec1, tel1, srs2-7AV) to assess complex reorganization and DNA damage sensitivity.

Main Results:

  • Srs2, Sgs1, and Mre11 form a large complex, potentially with other proteins.
  • This complex disassembles into Srs2-Mre11 and Sgs1-Mre11 subcomplexes after DNA damage, regulated by Mec1 and Tel1 kinases.
  • Mutations in Mec1, Tel1, or Srs2 (srs2-7AV) disrupt subcomplex formation and lead to hypersensitivity to intra-S DNA damage.

Conclusions:

  • Mec1 and Tel1 checkpoint pathways control the functional interactions within the Srs2-Sgs1-Mre11 complex.
  • Srs2 is a key target of the Cdk1-mediated cellular response to DNA damage, influencing complex dynamics and genome stability.

More Related Videos

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy11:40

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

Published on: June 25, 2013

Assessment of Global DNA Double-Strand End Resection using BrdU-DNA Labeling coupled with Cell Cycle Discrimination Imaging06:44

Assessment of Global DNA Double-Strand End Resection using BrdU-DNA Labeling coupled with Cell Cycle Discrimination Imaging

Published on: April 28, 2021

Related Concept Videos

S-Cdk Initiates DNA Replication02:38

S-Cdk Initiates DNA Replication

The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
S-Cdk Initiates DNA Replication02:38

S-Cdk Initiates DNA Replication

The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
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...
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...
Separation of Sister Chromatids02:17

Separation of Sister Chromatids

At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
The Spindle Assembly Checkpoint02:19

The Spindle Assembly Checkpoint

The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...