Reciprocal regulation of p63 by C/EBP delta in human keratinocytes

• Published in: BMC molecular biology Vol. 8; no. 1; p. 85
• Main Authors: Borrelli, Serena, Testoni, Barbara, Callari, Maurizio, Alotto, Daniela, Castagnoli, Carlotta, Romano, Rose-Anne, Sinha, Satrajit, Viganò, Alessandra M, Mantovani, Roberto
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 28.09.2007; BioMed Central
• Subjects: CCAAT-Enhancer-Binding Protein-delta - genetics; CCAAT-Enhancer-Binding Protein-delta - metabolism; Cell Differentiation - physiology; Cells, Cultured; DNA binding proteins; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Female; Gene Deletion; Gene Expression Profiling; Genetic aspects; Genetic screening; Health aspects; Humans; Identification and classification; Keratinocytes; Keratinocytes - cytology; Keratinocytes - metabolism; Oligonucleotide Array Sequence Analysis; Promoter Regions, Genetic - physiology; Protein Isoforms - genetics; Protein Isoforms - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Skin - cytology; Skin - metabolism; Trans-Activators - genetics; Trans-Activators - metabolism; Transcription Factors; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; United Kingdom
• ISSN: 1471-2199; 1471-2199
• DOI: 10.1186/1471-2199-8-85

Genetic experiments have clarified that p63 is a key transcription factor governing the establishment and maintenance of multilayered epithelia. Key to our understanding of p63 strategy is the identification of target genes. We perfomed an RNAi screening in keratinocytes for p63, followed by profiling analysis. C/EBPdelta, member of a family with known roles in differentiation pathways, emerged as a gene repressed by p63. We validated C/EBPdelta as a primary target of DeltaNp63alpha by RT-PCR and ChIP location analysis in HaCaT and primary cells. C/EBPdelta is differentially expressed in stratification of human skin and it is up-regulated upon differentiation of HaCaT and primary keratinocytes. It is bound to and activates the DeltaNp63 promoter. Overexpression of C/EBPdelta leads to alteration in the normal profile of p63 isoforms, with the emergence of DeltaNp63beta and gamma, and of the TA isoforms, with different kinetics. In addition, there are changes in the expression of most p63 targets. Inactivation of C/EBPdelta leads to gene expression modifications, in part due to the concomitant repression of DeltaNp63alpha. Finally, C/EBPdelta is found on the p63 targets in vivo by ChIP analysis, indicating that coregulation is direct. Our data highlight a coherent cross-talk between these two transcription factors in keratinocytes and a large sharing of common transcriptional targets.