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Updated: Aug 22, 2026

Yeast As a Chassis for Developing Functional Assays to Study Human P53
14:57

Yeast As a Chassis for Developing Functional Assays to Study Human P53

Published on: August 4, 2019

DNA-Peptide Crosslinks Placed at Codon 249 of the p53 Tumor Suppressor Gene Induce G to A Transitions in Human Cells

Priscilla Yawson1, Jan Henric T Bacurio1, Honnaiah Vijay Kumar2

  • 1Department of Chemistry, University of Connecticut, Storrs, Connecticut, USA.

Chembiochem : a European Journal of Chemical Biology
|August 21, 2026
PubMed

Insights

Anticancer drugs create DNA-protein cross-links (DPCs) that cells process into peptide-DNA cross-links (DpCs). This study shows specific DpCs are bypassed by DNA polymerases, with some polymerases aiding error-free bypass and others error-prone bypass.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Genetics

Background:

  • Anticancer nitrogen mustards form DNA-protein cross-links (DPCs).
  • Cells process DPCs into peptide-DNA cross-links (DpCs), enabling polymerase bypass.
  • The p53 tumor suppressor gene's codon 249 is a mutational hotspot.

Purpose of the Study:

  • To create and study DNA lesions mimicking nitrogen mustard-induced DpCs.
  • To investigate the translesion synthesis (TLS) of these DpCs in human cells.
  • To determine the roles of specific DNA polymerases in bypassing DpCs.

Main Methods:

  • Generated site-specific, stable DNA lesions resembling DpCs using oxime ligation.
  • Constructed DNA containing a peptide from histone H4 and a modified guanine base.
  • Performed TLS experiments in wild-type and knockout human HEK 293T cells for various DNA polymerases (Pol ι, η, κ, ζ).

Main Results:

  • The 7-deaza-DpC lesion was efficiently bypassed in wild-type cells (83%).
  • Bypass efficiency was reduced in Pol ι (53%), Pol η (59%), and Pol κ (63%) knockout cells.
  • Mutation frequency was higher for DpC bypass (~9%) than the control (~5%).
  • Pol η and Pol ι deficiency increased error rates, indicating roles in error-free bypass.
  • Pol ζ deficiency decreased mutation rates, suggesting a role in error-prone bypass.

Conclusions:

  • DNA polymerases play distinct roles in the bypass of peptide-DNA cross-links.
  • Pol η and Pol ι appear to mediate error-free translesion synthesis of DpCs.
  • Pol ζ may be involved in error-prone bypass of these DNA lesions.
Keywords:
DNA damageDNA–protein crosslinksmutationspolymerase bypasstumor suppressor gene

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