p73 and p63 regulate the expression of fibroblast growth factor receptor 3

p53, p63 and p73 make a family of transcription factors that play a vital role in development and cancer. Allp53 family members have more than one promoter producing Transactivating (TA) and Dominant Negative(DN) isoforms and theirmRNAs are subjected to extensive splicing at30 endto producemultiple protein products.p53 is usually inactivated by point mutations during tumorigenesis, whereas the expression levels andp63andp73aremodulatedto givetumor cells a selective advantage. In this study, aiming tofindnovel targetsof the p53 familymembers,weidentified FGFR3 as a gene transcriptionally controlled by p63 and p73. FGFR3has been implicated in development and tumor biology as activating mutations of this gene was described inskeletal disorders, non-invasive skin conditions and superficial bladder cancers.Wefound that TAp73, TAp63and DNp63 was capable of inducing FGFR3. siRNA mediated downregulation of DNp63 decreased endogenousFGFR3 protein levels. Our findings of this new link between p53 family proteins and FGFR3 may helpunderstanding the transition of superficial bladder cancers to an invasive phenotype.