ChIP-seq analysis identifies p27(Kip1)-target genes involved in cell adhesion and cell signalling in mouse embryonic fibroblasts

The protein p27(Kip1), a member of the Cip-Kip family of cyclin-dependent kinase inhibitors, has been recently identified as a transcriptional regulator. However, the transcriptional programs regulated by this protein, still remain mostly unknown. The aim of this study has been to define the transcriptional programs regulated by p27 by first identifying the p27-binding sites on the whole chromatin of quiescent mouse embryonic fibroblasts by Chromatin Immunoprecipitation Sequencing (ChIP-seq). Results revealed that most of the p27 binding sites were in distal intergenic regions and introns whereas, in contrast, its association with promoter regions was very low. Gene ontology analysis of the protein coding genes revealed a number of relevant transcriptional programs regulated by p27 as cell adhesion, intracellular signalling and neuron differentiation among others. We validated the interaction of p27 with different chromatin regions by ChIP followed by qPCR and demonstrated that the expressions of several genes belonging to these programs are actually regulated by p27.