Sp1 is involved in the transcriptional activation of p16INK4 by p21Waf1 in HeLa cells

AbstractBoth p16INK4 and p21Waf1 are very important negative regulators of the cell cycle. In this study we examined the effects of p21Waf1 on the transcription of p16INK4. We determined that p21Waf1 can activate the transcription of p16INK4, and that this effect is GC-box dependent. We also found that the transcription factor Sp1 plays a key role in this event. Upregulation of Sp1 contributes to the transcriptional activation and protein level of p16INK4 mediated by p21Waf1, and is a potential point of cooperation between the p16/pRb and p14 (ARF)/p53 tumor suppressor pathways