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Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins
10:24

Two- and Three-Dimensional Live Cell Imaging of DNA Damage Response Proteins

Published on: September 28, 2012

The novel DNA damage checkpoint protein ddc1p is phosphorylated periodically during the cell cycle and in response to

M P Longhese1, V Paciotti, R Fraschini

  • 1Dipartimento di Genetica e di Biologia dei Microrganismi, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.

The EMBO Journal
|October 6, 1997
PubMed

Insights

The DDC1 gene is crucial for DNA damage checkpoints, halting cell cycle progression to allow DNA repair. Its absence leads to sensitivity to DNA-damaging agents and cell cycle delays.

Area of Science:

  • Cellular biology
  • Molecular genetics
  • DNA repair mechanisms

Background:

  • The DDC1 gene was identified through screening for mutations causing synthetic lethality with altered DNA primase.
  • Deletion of DDC1 results in sensitivity to UV radiation, methyl methanesulfonate (MMS), and hydroxyurea (HU).

Purpose of the Study:

  • To investigate the role of the DDC1 gene in DNA damage checkpoints and cell cycle regulation.
  • To understand the relationship between DDC1, MEC3, and other checkpoint genes.

Main Methods:

  • Screening for synthetic lethality mutations.
  • Phenotypic analysis of ddc1Delta mutants, including sensitivity assays and cell cycle progression studies.
  • Epistasis analysis and gene overexpression studies.

Main Results:

  • ddc1Delta mutants exhibit defects in G1-S and G2-M transitions and DNA synthesis rate upon DNA damage.
  • DDC1 is implicated in all known DNA damage checkpoints, but not in delaying mitosis when DNA synthesis is inhibited.
  • DDC1 and MEC3 belong to the same epistasis group, with DDC1 overexpression partially suppressing mec3Delta sensitivity and checkpoint defects.
  • Ddc1p undergoes periodic and damage-induced hyperphosphorylation, partially dependent on MEC3.

Conclusions:

  • DDC1 plays a critical role in multiple DNA damage checkpoint pathways.
  • Ddc1p phosphorylation is regulated by DNA damage and is linked to MEC3 function.
  • DDC1 is essential for maintaining genomic stability in response to DNA damage.

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