Related Experiment Video

Updated: Aug 7, 2026

Proofreading and DNA Repair Assay Using Single Nucleotide Extension and MALDI-TOF Mass Spectrometry Analysis
11:08

Proofreading and DNA Repair Assay Using Single Nucleotide Extension and MALDI-TOF Mass Spectrometry Analysis

Published on: June 19, 2018

Characterization of the "mismatch repairosome" and its role in the processing of modified nucleosides in vitro

Katja Baerenfaller1, Franziska Fischer, Josef Jiricny

  • 1Institute of Molecular Cancer Research, University of Zurich, Switzerland.

Methods in Enzymology
|June 24, 2006
PubMed

Insights

Postreplicative mismatch repair (MMR) enhances DNA replication accuracy by correcting errors. This study explores MMR protein roles in DNA repair and modified nucleoside processing using in vitro systems and specialized DNA substrates.

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Postreplicative mismatch repair (MMR) is crucial for maintaining DNA replication fidelity by correcting biosynthetic errors.
  • MMR proteins also participate in processing recombination intermediates and signaling DNA damage in mammalian cells.
  • Studying MMR's molecular mechanisms is limited to in vitro systems due to the inability to induce mismatches in vivo.

Purpose of the Study:

  • To describe the construction of heteroduplex DNA substrates for studying eukaryotic MMR proteins.
  • To enable DNA affinity purification of MMR protein complexes using these substrates.
  • To investigate the role of MMR proteins in processing modified nucleosides.

Main Methods:

  • Construction of specific heteroduplex DNA substrates.
  • Application of DNA affinity purification techniques for MMR protein complex isolation.
  • In vitro assays to study the processing of modified nucleosides by MMR proteins.

Main Results:

  • Successfully developed heteroduplex substrates suitable for MMR research.
  • Demonstrated the utility of these substrates for purifying MMR protein complexes.
  • Provided a framework for investigating MMR's role in modified nucleoside metabolism.

Conclusions:

  • The described heteroduplex substrates are valuable tools for in vitro MMR studies.
  • These methods facilitate the purification and functional analysis of eukaryotic MMR proteins.
  • Further research can elucidate MMR's involvement in processing modified nucleosides and its broader genomic stability functions.

More Related Videos

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein11:01

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein

Published on: March 31, 2010

Studying Ribonucleotide Incorporation: Strand-specific Detection of Ribonucleotides in the Yeast Genome and Measuring Ribonucleotide-induced Mutagenesis09:04

Studying Ribonucleotide Incorporation: Strand-specific Detection of Ribonucleotides in the Yeast Genome and Measuring Ribonucleotide-induced Mutagenesis

Published on: July 26, 2018

Related Concept Videos

Mismatch Repair01:36

Mismatch Repair

Overview
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...
Mismatch Repair01:36

Mismatch Repair

Overview
Proofreading01:31

Proofreading

Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore,  it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Proofreading01:43

Proofreading

Synthesis of new DNA molecules starts when DNA polymerase links nucleotides together in a sequence that is complementary to the template DNA strand. DNA polymerase has a higher affinity for the correct base to ensure fidelity in DNA replication. The DNA polymerase furthermore proofreads during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.Errors during Replication Are Corrected by the DNA Polymerase EnzymeGenomic DNA is synthesized in...
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...