p16INK4a translation suppressed by miR-24

Abstract

Background: Expression of the tumor suppressor p16INK4a increases during aging and replicative senescence. Methodology/principal findings: Here we report that the microRNA miR-24 suppresses p16 expression in human diploid fibroblasts and cervical carcinoma cells. Increased p16 expression with replicative senescence was associated with decreased levels of miR-24, a microRNA that was predicted to associate with the p16 mRNA coding and 3′-untranslated regions. Ectopic miR-24 overexpression reduced p16 protein but not p16 mRNA levels. Conversely, introduction of antisense (AS)-miR-24 blocked miR-24 expression and markedly enhanced p16 protein levels, p16 translation, and the production of EGFP-p16 reporter bearing the miR-24 target recognition sites. Conclusions/significance: Together, our results suggest that miR-24 represses the initiation and elongation phases of p16 translation.