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Mutagenesis in vivo in T cells of p21-deficient mice

Changshun Shao1, Li Liang, Xin Zhao

  • 1Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA. shao@biology.rutgers.edu

Mutation Research
|September 12, 2009
PubMed

Insights

Mice lacking p21, a protein that halts cell division after DNA damage, show fewer mutations in T cells and resistance to thymic lymphoma. This suggests p21

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Genetics

Background:

  • p53 tumor suppressor protein is crucial for preventing cancer.
  • p21(Cip1/Waf1) is a downstream effector of p53, regulating the cell cycle.
  • p21 deficiency increases tumor incidence but paradoxically reduces thymic lymphomagenesis.

Purpose of the Study:

  • To investigate the role of p21 in mutagenesis within T cells.
  • To understand the impact of p21 deficiency on DNA damage-induced mutations.
  • To elucidate the mechanisms underlying p21's tumor suppressor activity in thymic lymphomagenesis.

Main Methods:

  • Utilized p21-deficient (p21-/-) and wild-type (p21+/+) mice.
  • Assessed mutagenesis in T cells using loss of heterozygosity (LOH) at the Aprt locus.
  • Exposed mice to X-rays to study radiation-induced mutagenesis and apoptosis.

Main Results:

  • Spontaneous Aprt mutant frequency was lower in p21-/- mice compared to p21+/+ mice.
  • Mitotic recombination was the predominant mutational pathway in both genotypes.
  • X-ray-induced LOH was not significantly increased in p21-/- mice, unlike in p53-/- mice.
  • Lymphoid cells from p21-/- mice exhibited increased sensitivity to IR-induced apoptosis.

Conclusions:

  • Reduced mutation load in T cell lineages may contribute to the observed resistance to thymic lymphomagenesis in p21-/- mice.
  • p21 plays a significant role in suppressing mutagenesis and promoting apoptosis in response to DNA damage.
  • These findings highlight distinct roles of p53 and p21 in tumor suppression and mutagenesis.

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