Remodelling chromatin on a global scale: a novel protective function of p53.

The tumour suppressor p53 has an essential role in maintaining the genomic integrity of the mammalian cell. This is achieved in part through its function as a transcription factor enabling it to induce either growth arrest or apoptosis in response to cellular stress. Changes in gene expression commonly require localized chromatin remodelling and p53 is known to interact in vivo with a variety of transcriptional co-activators and co-repressors with intrinsic histone modifying activities. Here we examine the links between p53 and chromatin structures associated with (i) transcriptional regulation of gene expression, (ii) with DNA repair as part of the process of nucleotide excision repair and (iii) with histone modifications which impact upon chromosomal condensation and ploidy.