Delta Np63 transcriptionally regulates ATM to control p53 Serine-15 phosphorylation

作者：Craig Ashley L; Holcakova Jitka; Finlan Lee E; Nekulova Marta; Hrstka Roman; Gueven Nuri; DiRenzo James; Smith Graeme; Hupp Ted R; Vojtesek Borivoj^*

来源：Molecular Cancer, 2010, 9: 195.

DOI：10.1186/1476-4598-9-195

Background: Delta Np63 alpha is an epithelial progenitor cell marker that maintains epidermal stem cell self-renewal capacity. Previous studies revealed that UV-damage induced p53 phosphorylation is confined to Delta Np63 alpha-positive cells in the basal layer of human epithelium.
Results: We now report that phosphorylation of the p53 tumour suppressor is positively regulated by Delta Np63 alpha in immortalised human keratinocytes. Delta Np63 alpha depletion by RNAi reduces steady-state ATM mRNA and protein levels, and attenuates p53 Serine-15 phosphorylation. Conversely, ectopic expression of Delta Np63 alpha in p63-null tumour cells stimulates ATM transcription and p53 Serine-15 phosphorylation. We show that ATM is a direct Delta Np63 alpha transcriptional target and that the Delta Np63 alpha response element localizes to the ATM promoter CCAAT sequence. Structure-function analysis revealed that the Delta Np63-specific TA2 transactivation domain mediates ATM transcription in coordination with the DNA binding and SAM domains.
Conclusions: Germline p63 point mutations are associated with a range of ectodermal developmental disorders, and targeted p63 deletion in the skin causes premature ageing. The Delta Np63 alpha-ATM-p53 damage-response pathway may therefore function in epithelial development, carcinogenesis and the ageing processes.

• 出版日期2010-7-21
• 单位河北医科大学