title: A human temperature-sensitive p53 mutant p53Val-138: modulation of the cell cycle, viability and expression of p53-responsive genes.
abstract: A human p53 mutant, p53Val-138 (amino acid 138, Alanine-->Valine), generated by in vitro mutagenesis was introduced into Saos-2 human osteosarcoma and Jurkat acute T-lymphoblastic leukemia cell lines, both lacking p53 protein expression. p53Val-138 caused growth arrest in Saos-2 cell line and apoptosis in Jurkat cell line at 32.5 degrees C while it allowed both cell lines to grow continuously at 37.5 degrees C. p53Val-138 activated expression of p53-responsive genes including MDM2, GADD45 and WAF1/CIP1/SD11 in Saos-2 cell line upon the temperature shift-down from 37.5 degrees C to 32.5 degrees C. Thus, p53Val-138 acted as a temperature-sensitive p53 mutant. Taking advantage of these human cell systems, we demonstrated that p53-mediated cell cycle arrest occurred in G1 and G2/M phases of Saos-2 cell line but not in Jurkat cell line. The induced level of WAF1/CIP1/SDI1 mRNA by p53 was extremely lower in Jurkat cell line than that of Saos-2 cell line. However, MDM2 mRNA accumulated to the similar levels in these two cell lines. These results suggest that a factor(s) other than p53 may be involved in differential expression of WAF1/CIP1/SDI1 and MDM2 mRNA.
authors.affiliation: Department of Molecular Cellular Oncology and Microbiology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamato
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Hirano
authors.forename: N
authors.initials: N
authors.lastname: Tsuchida
mesh_terms: D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D002470:Cell Survival / Q000235:genetics; D005786:Gene Expression Regulation; D016158:Genes, p53; D006801:Humans; D013696:Temperature; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D014633:Valine / Q000235:genetics*
chemical_list: D016159:Tumor Suppressor Protein p53; D014633:Valine