ACCUMULATION OF P16(CDKN2A) IN RESPONSE TO ULTRAVIOLET-IRRADIATION CORRELATES WITH A LATE S-G(2)-PHASE CELL-CYCLE DELAY

p16 is the product of the CDKN2A locus, which is mutated or deleted in many human tumors, In response to nonlethal UVC irradiation, HeLa cel ls accumulate elevated levels of p16. The accumulation of p16 is delay ed 8-12 h following irradiation and correlates with S-phase and G(2) d elays, decreasing as the cells recover and recommence normal cell grow th, The maximum levels of p16 correlated with G(2) delay, The UVC-indu ced cell cycle delay was absent in cell lines derived from HeLa that d id not express p16 and in a melanoma line deleted for p16.