Sensitivity and selectivity of the DNA damage sensor responsible for activating p53-dependent G1 arrest.
The tumor suppressor p53 contributes to maintaining genome stability by inducing a cell cycle arrest or apoptosis in response to conditions that generate DNA damage. Nuclear injection of linearized plasmid DNA, circular DNA with a large gap, or single-stranded circular phagemid is sufficient to induce a p53-dependent arrest. Supercoiled and nicked plasmid DNA, and circular DNA with a small gap were ineffective. Titration experiments indicate that the arrest mechanism in normal human fibroblasts can be activated by very few double strand breaks, and only one may be sufficient. Polymerase chain reaction assays showed that end-joining activity is low in serum-arrested human fibroblasts, and that higher joining activity occurs as cells proceed through G1 or into S phase. We propose that the exquisite sensitivity of the p53-dependent G1 arrest is partly due to inefficient repair of certain types of DNA damage in early G1.
Huang
L C
LC
Gene Expression Laboratory, The Salk Institute, San Diego, CA 92037, USA.
Clarkin
K C
KC
Wahl
G M
GM
D001483:Base Sequence; D002453:Cell Cycle / Q000235:genetics; D002460:Cell Line; D004247:DNA / Q000235:genetics; D004249:DNA Damage; D017931:DNA Primers / Q000235:genetics; D004260:DNA Repair / Q000235:genetics; D016193:G1 Phase / Q000235:genetics*; D016158:Genes, p53; D006801:Humans; D008845:Microinjections; D008969:Molecular Sequence Data; D010957:Plasmids / Q000008:administration & dosage / Q000235:genetics; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity
D017931:DNA Primers; D004247:DNA