VENTX binds to the CDKN2A promoter that regulates the expression of the p16-INK4A cyclin-dependent kinase inhibitor. Binding of VENTX to an alternative CDKN2A promoter, which regulates the expression of p14-ARF, has not been examined (Wu et al. 2011). CDKN2A locus encodes tumor suppressor genes p16INK4A and p14ARF (p19ARF in mouse). p16INK4A and p14ARF are expressed from different promoters and translated in different reading frames. They use different exon 1 (exon 1-alpha in p16INK4A and exon 1-beta in p14ARF) but share exons 2 and 3. Therefore, while their mRNAs are homologous, they share no similarity at the amino acid sequence level and perform distinct functions in the cell (Quelle et al. 1995).