Dataset Information

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

ABSTRACT:

Background

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.

Results

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.

Conclusion

Our data highlight a coherent cross-talk between these two transcription factors in keratinocytes and a large sharing of common transcriptional targets.

SUBMITTER: Borrelli S

PROVIDER: S-EPMC2148061 | biostudies-literature | 2007 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Borrelli Serena S Testoni Barbara B Callari Maurizio M Alotto Daniela D Castagnoli Carlotta C Romano Rose-Anne RA Sinha Satrajit S Viganò Alessandra M AM Mantovani Roberto R

BMC molecular biology 20070928

<h4>Background</h4>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.<h4>Results</h4>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 tar ...[more]

PMID: 17903252

Similar Datasets

Project description:ABCA12 (ATP binding cassette transporter, family 12) is a cellular membrane transporter that facilitates the delivery of glucosylceramides to epidermal lamellar bodies in keratinocytes, a process that is critical for permeability barrier formation. Following secretion of lamellar bodies into the stratum corneum, glucosylceramides are metabolized to ceramides, which comprise approximately 50% of the lipid in stratum corneum. Gene mutations of ABCA12 underlie harlequin ichthyosis, a devastating skin disorder characterized by abnormal lamellar bodies and a severe barrier abnormality. Recently we reported that peroxisome proliferator-activated receptor (PPAR) and liver X receptor activators increase ABCA12 expression in human keratinocytes. Here we demonstrate that ceramide (C(2)-Cer and C(6)-Cer), but not C(8)-glucosylceramides, sphingosine, or ceramide 1-phosphate, increases ABCA12 mRNA expression in a dose- and time-dependent manner. Inhibitors of glucosylceramide synthase, sphingomyelin synthase, and ceramidase and small interfering RNA knockdown of human alkaline ceramidase, which all increase endogenous ceramide levels, also increased ABCA12 mRNA levels. Moreover, simultaneous treatment with C(6)-Cer and each of these same inhibitors additively increased ABCA12 expression, indicating that ceramide is an important inducer of ABCA12 expression and that the conversion of ceramide to other sphingolipids or metabolites is not required. Finally, both exogenous and endogenous ceramides preferentially stimulate PPARdelta expression (but not other PPARs or liver X receptors), whereas PPARdelta knockdown by siRNA transfection specifically diminished the ceramide-induced increase in ABCA12 mRNA levels, indicating that PPARdelta is a mediator of the ceramide effect. Together, these results show that ceramide, an important lipid component of epidermis, up-regulates ABCA12 expression via the PPARdelta-mediated signaling pathway, providing a substrate-driven, feed-forward mechanism for regulating this key lipid transporter.

Dataset Information

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

Background

Results

Conclusion

Publications

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

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets