title: p53 gene mutation and loss of heterozygosity of chromosome 11 in methylcholanthrene-induced mouse sarcomas.
abstract: Mutations of the p53 tumor suppressor gene are the most prevalent genetic alteration observed in a wide variety of human cancers. In this study we examined 63 methylcholanthrene (MCA)-induced sarcomas from C57BL/6N x C3H/HeN F1 (BCF1) or C3H/HeN x C57BL/6N F1 (CBF1) mice for p53 gene mutations and loss of heterozygosity (LOH) of chromosome 11. Mutation analysis was done on exons 5 to 8 of the p53 gene by polymerase chain reaction-single strand conformation polymorphism analysis. This identified 53 potential mutations in 45 sarcomas. Mutations were further confirmed by direct sequencing of the region. Forty-nine of the 53 cases (94%) were missense mutations, while the rest included two nonsense mutations, one silent mutation and one insertional mutation. Spectra of base substitutions were: 25 cases (47%) of G:C-->T:A transversion, 13 cases (25%) of G:C-->A:T transition (CpG site 15%), 13 cases (24%) of G:C-->C:G transversion, a case (2%) of A:T-->T:A transversion and a case (2%) of insertion. In addition, analysis of 5 polymorphic markers of mouse chromosome 11 revealed LOH in ten cases (22%) among those carrying p53 mutations. In nine of these 10 cases, the loss involved all 5 markers. In addition, the loss was biased toward the C57BL allele (9 cases). The present study establishes the pattern of mutation of the p53 gene in MCA-induced mouse sarcomas.
authors.affiliation: Second Department of Surgery, School of Medicine, Hiroshima University.
authors.forename: K
authors.initials: K
authors.lastname: Shimokado
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Sumii
authors.forename: K
authors.initials: K
authors.lastname: Miyagawa
authors.forename: K
authors.initials: K
authors.lastname: Kamiya
authors.forename: K
authors.initials: K
authors.lastname: Dohi
authors.forename: O
authors.initials: O
authors.lastname: Niwa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016158:Genes, p53; D006801:Humans; D019656:Loss of Heterozygosity; D008748:Methylcholanthrene; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D009154:Mutation; D017354:Point Mutation; D012513:Sarcoma, Experimental / Q000139:chemically induced / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D008748:Methylcholanthrene