∆Np63 cooperates with the FOX family members to regulate cell motility genes. A, qRT-PCR for the indicated ΔNp63-specific target genes in epidermal cells of the indicated genotype. Data are mean ± SD, n = 3, * versus WT, P < 0.005, two-tailed t test. B, qRT-PCR of ∆Np63 ChIP assays using epidermal cells of the indicated genotype on the ∆Np63-specific peaks of the indicated ΔNp63-specific target genes. Data are mean ± SD, n = 3, * versus WT, P < 0.005, two-tailed t test. C, qRT-PCR of Foxj2 ChIP-re-ChIP assays using the ∆Np63 chromatin immunoprecipitated genomic regions of the indicated ΔNp63-specific target genes from epidermal cells of the indicated genotype. Data are mean ± SD, n = 3. * versus WT, P < 0.005, two-tailed t test. D, qRT-PCR of the indicated ΔNp63-specific target genes in WT, ΔNp63−/−, and TAp63−/− epidermal cells transfected with the indicated siRNAs. Data are mean ± SD, n = 3, * versus WT siControl, # versus WT siFoxj2, and $ versus WT siFoxl1, P < 0.005, two-tailed t test. E, Model depicting the coordinated regulation of ∆Np63-specific cell motility genes by ∆Np63 and the FOX family members, FoxJ2 and Foxl1. F, Representative Western blot analysis using the indicated antibodies of the endogenous interacting proteins immunoprecipitated with p63 isoform–specific antibodies. IgGs from normal rabbit serum were used as negative control. Protein inputs (5% of lysates) are also shown.
Funding
HHS | NIH | National Cancer Institute (NCI)
Cancer Prevention and Research Institute of Texas (CPRIT)
HHS | National Institutes of Health (NIH)
HHS | NIH | National Institute of Environmental Health Sciences (NIEHS)
ARTICLE ABSTRACT
The p53 family member TP63 encodes two sets of N-terminal isoforms, TAp63 and ΔNp63 isoforms. They each regulate diverse biological functions in epidermal morphogenesis and in cancer. In the skin, where their activities have been extensively characterized, TAp63 prevents premature aging by regulating the quiescence and genomic stability of stem cells required for wound healing and hair regeneration, while ΔNp63 controls maintenance and terminal differentiation of epidermal basal cells. This functional diversity is surprising given that these isoforms share a high degree of similarity, including an identical sequence for a DNA-binding domain. To understand the mechanisms of the transcriptional programs regulated by each p63 isoform and leading to diverse biological functions, we performed genome-wide analyses using p63 isoform-specific chromatin immunoprecipitation, RNA sequencing, and metabolomics of TAp63−/− and ΔNp63−/− mouse epidermal cells. Our data indicate that TAp63 and ΔNp63 physically and functionally interact with distinct transcription factors for the downstream regulation of their target genes, thus ultimately leading to the regulation of unique transcriptional programs and biological processes. Our findings unveil novel transcriptomes regulated by the p63 isoforms to control diverse biological functions, including the cooperation between TAp63 and NRF2 in the modulation of metabolic pathways and response to oxidative stress providing a mechanistic explanation for the TAp63 knock out phenotypes.
The p63 isoforms, TAp63 and ΔNp63, control epithelial morphogenesis and tumorigenesis through the interaction with distinct transcription factors and the subsequent regulation of unique transcriptional programs.
