Using microarray analysis, Kim and colleagues revealed that the level of cyclin-dependent kinase inhibitor 1A (CDKN1A; also known as Waf1/p21) mRNAs increases in cells depleted of cellular NMD factors. Interestingly, p21 mRNA contains an uORF, which is a NMD-inducing feature. Using several approaches, they identified the uORF in CDKN1A mRNA as a negative modulator of translation of the main downstream ORF, thus providing additional biological evidence of the possible role of NMD in diverse biological pathways.94
