title: P53 (codon 72) and P21 (codon 31) polymorphisms alter in vivo mRNA expression of p21.
abstract: p21 (Waf1/Cip1) is a downstream target of p53. We evaluated the association between p21 polymorphism (codon 31), p53 polymorphism (codon 72) and their corresponding in vivo mRNA expression. In this study, p21 and p53 genetic polymorphisms (using standard PCR-RFLP techniques) and p21 and p53 gene expressions (using a radiolabelled ribonuclease protection assay (RPA) technique) were evaluated in the peripheral leukocytes of 84 individuals (63 with lung cancer). Log-transformed values of mRNA expression by RPA, which approximated a normal distribution, were analyzed. p53 genotypes did not correlate with p53 mRNA log-expression (P>0.05 for all comparisons), but the Pro allele variants of p53 were associated with a significant decrease in mRNA log-expression of its downstream target, p21. The variant Arg allele of p21 was also associated with a significant decrease in p21 mRNA log-expression. When individuals with at least one variant allele of both p53 and p21 (double-variants) were compared with all other genotype groups, these double-variants had significantly lower log-expression of p21 (P<0.005 by both t-tests (crude) and linear regression analyses (adjusted)). This is translated into an approximate 48% reduction in the geometric mean of the mRNA expression of the double-variants, when compared with all other groups. Results were consistent in both patients with lung cancer (n=63) and in normal controls (n=21). In conclusion, the presence of a p53 Pro allele and/or p21 Arg allele is associated with lower downstream target gene expression of p21.
authors.affiliation: Occupational Health Program, Department of Environmental Health, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Su
authors.forename: Yang
authors.initials: Y
authors.lastname: Sai
authors.forename: Rong
authors.initials: R
authors.lastname: Fan
authors.forename: Sally W
authors.initials: SW
authors.lastname: Thurston
authors.forename: David P
authors.initials: DP
authors.lastname: Miller
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: John C
authors.initials: JC
authors.lastname: Wain
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Lynch
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Liu
authors.forename: David C
authors.initials: DC
authors.lastname: Christiani
mesh_terms: D000368:Aged; D000483:Alleles; D001120:Arginine; D018929:Cell Culture Techniques; D003062:Codon; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis* / Q000235:genetics*; D004791:Enzyme Inhibitors; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016158:Genes, p53 / Q000235:genetics*; D006801:Humans; D007962:Leukocytes; D008175:Lung Neoplasms / Q000235:genetics* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: C493956:CDKN1A protein, human; D003062:Codon; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D001120:Arginine