Requirement of wild-type p53 protein for maintenance of chromosomal integrity

Masamitsu Honma, Maki Momose, Hideyuki Tanabe, Hiroko Sakamoto, Yongjia Yu, John B. Little, Toshio Sofuni, Makoto Hayashi

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Chromosomal double-strand breaks (DSBs) occurring in mammalian cells can initiate genomic instability, and their misrepairs result in chromosomal deletion, amplification, and translocation, common findings in human tumors. The tumor-suppressor protein p53 is involved in maintaining genomic stability. In this study, we demonstrate that the deficiency of wild-type p53 protein may allow unrepaired DSBs to initiate chromosomal instability. The human lymphoblastoid cell line TK6-E6 was established by transfection with human papilloma virus 16 (HPV16) E6 cDNA into parental TK6 cells via a retroviral vector. Abrogation of p53 function by E6 resulted in an increase in the spontaneous mutation frequencies at the heterozygous thymidine kinase (TK) locus but not at the hemizygous hypoxanthine phosphoribosyl transferase (HPRT) locus. Almost all TK-deficient mutants from TK6-E6 cells exhibited loss of heterozygosity (LOH) with the hemizygous TK allele. LOH analysis with microsatellite loci spanning the long arm of chromosome 17, which harbors the TK locus, showed that LOH extended over half of 17q toward the terminal end. Cytogenetic analysis of LOH mutants by chromosome painting indicated a mosaic of chromosomal aberrations involving chromosome 17, in which partial chromosome deletions, amplifications, and multiple translocations appeared heterogeneously in a single mutant. We speculate that spontaneous DSBs trigger the breakage-fusion bridge cycle leading to such multiple chromosome aberrations. In contrast, no chromosomal alterations were observed in TK-deficient mutants from TK6-20C cells expressing wild-type p53. In wild-type p53 cells, spontaneous DSBs appear to be promptly repaired through recombination between homologous chromosomes. These results support a model in which p53 protein contributes to the maintenance of genomic integrity through recombinational repair. (C) 2000 Wiley-Liss, Inc.

Original languageEnglish (US)
Pages (from-to)203-214
Number of pages12
JournalMolecular Carcinogenesis
Volume28
Issue number4
DOIs
StatePublished - 2000
Externally publishedYes

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Thymidine Kinase
Loss of Heterozygosity
Maintenance
Chromosomes, Human, Pair 17
Genomic Instability
Proteins
Papillomaviridae
Chromosome Aberrations
Chromosome Painting
Tumor Suppressor Protein p53
Chromosome Deletion
Chromosomal Instability
Hypoxanthine
Cytogenetic Analysis
Mutation Rate
Transferases
Microsatellite Repeats
Genetic Recombination
Transfection
Complementary DNA

Keywords

  • Double-strand breaks
  • Genomic instability
  • Loss of heterozygosity
  • p53
  • Recombinational DNA repair

ASJC Scopus subject areas

  • Cancer Research
  • Molecular Biology

Cite this

Requirement of wild-type p53 protein for maintenance of chromosomal integrity. / Honma, Masamitsu; Momose, Maki; Tanabe, Hideyuki; Sakamoto, Hiroko; Yu, Yongjia; Little, John B.; Sofuni, Toshio; Hayashi, Makoto.

In: Molecular Carcinogenesis, Vol. 28, No. 4, 2000, p. 203-214.

Research output: Contribution to journalArticle

Honma, M, Momose, M, Tanabe, H, Sakamoto, H, Yu, Y, Little, JB, Sofuni, T & Hayashi, M 2000, 'Requirement of wild-type p53 protein for maintenance of chromosomal integrity', Molecular Carcinogenesis, vol. 28, no. 4, pp. 203-214. https://doi.org/10.1002/1098-2744(200008)28:4<203::AID-MC3>3.0.CO;2-1
Honma, Masamitsu ; Momose, Maki ; Tanabe, Hideyuki ; Sakamoto, Hiroko ; Yu, Yongjia ; Little, John B. ; Sofuni, Toshio ; Hayashi, Makoto. / Requirement of wild-type p53 protein for maintenance of chromosomal integrity. In: Molecular Carcinogenesis. 2000 ; Vol. 28, No. 4. pp. 203-214.
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