Following DNA-damage, the tumor suppressor p53 activates G(1)/S blocking and apoptotic genes, and represses other genes, including those involved in G(2)/M transition. In this latter system, it acts through the CCAAT-binding histone-like NF-Y. Several groups have reported that p53 is associated to promoters in unstressed conditions. We developed an oligo-based array containing 179 human promoters, enriched in genes involved in the DNA-damage and ER-stress response. We performed ChIP on chip experiments with p53 and NF-Y in cells under normal growing conditions. We identified 46 new p53 targets and noted (i) a significant enrichment in genes of the ER-stress response, including crucial regulators such as XBP1 and C/EBP beta; (ii) genes whose products are involved in the regulation of p53 function. Several genes were validated by conventional ChIP. DNA-damage dependent PCAF-mediated acetylation was observed on most, but not all promoters. The effect of p53 activation was checked by RT-PCR and transfections in HCT116 wt, E6 and p53(-/-) cells: most promoters were actively repressed upon Adriamycin treatment or following p53 transfection in p53-/- cells. In particular, the behaviour of some of the genes (BRCA1, RAD23 and RAD17) is consistent with a feedback loop regulation on p53 levels. Finally, there is a large overlap (66%) between p53 and NF-Y targets. Our data reinstate the physiological importance of p53 promoter recognition and direct transcriptional repression as a mechanism to cope with DNA-damage.
Repression of New p53 Targets Revealed by ChIP on Chip Experiments / M. Ceribelli, M. Alcalay, M.A. Viganò, R. Mantovani. - In: CELL CYCLE. - ISSN 1538-4101. - 5:10(2006 May 15), pp. 1102-1110.
|Titolo:||Repression of New p53 Targets Revealed by ChIP on Chip Experiments|
CERIBELLI, MICHELE (Primo)
ALCALAY, MYRIAM (Secondo)
VIGANO', MARIA ALESSANDRA (Penultimo)
MANTOVANI, ROBERTO (Ultimo)
|Parole Chiave:||ChIP on chip ; p53 ; NF-Y ; repression|
|Settore Scientifico Disciplinare:||Settore BIO/18 - Genetica|
|Data di pubblicazione:||15-mag-2006|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.4161/cc.5.10.2777|
|Appare nelle tipologie:||01 - Articolo su periodico|