An autoregulatory loop directs the tissue-specific expression of p63 through a long-range evolutionarily conserved enhancer.
p63, a p53 family member, is essential for the development of various stratified epithelia and is one of the earliest markers of many ectodermal structures, including the epidermis, oral mucosa, apical ectodermal ridge, and mammary gland. Genetic regulatory mechanisms controlling p63 spatial expression during development have not yet been defined. Using a genomic approach, we identified an evolutionarily conserved cis-regulatory element, located 160 kb downstream of the first p63 exon, which functions as a keratinocyte-specific enhancer and is sufficient to recapitulate expression of the endogenous gene during mouse embryogenesis. Dissection of the p63 enhancer activity revealed a positive autoregulatory loop in which the p63 proteins directly bind to and are essential regulators of the enhancer. Accordingly, transactivating p63 isoforms induce endogenous p63 expression in cells that do not normally express this gene, whereas dominant negative isoforms suppress p63 expression in keratinocytes. In addition the transcription factor AP-2 also binds to the enhancer and cooperates with p63 to induce its activity. These results demonstrate that a long-range autoregulatory loop is involved in the regulation of p63 expression during embryonic development and in adult cells.
Telethon Institute of Genetics and Medicine, Via Pietro Castellino 111, 80131 Naples, Italy.
Dario
D
Antonini
Barbara
B
Rossi
Rong
R
Han
Annunziata
A
Minichiello
Tina
T
Di Palma
Marcella
M
Corrado
Sandro
S
Banfi
Mariastella
M
Zannini
Janice L
JL
Brissette
Caterina
C
Missero
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D017124:Conserved Sequence; D024202:Electrophoretic Mobility Shift Assay; D004742:Enhancer Elements, Genetic; D019143:Evolution, Molecular; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009154:Mutation; D041681:NIH 3T3 Cells; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D050656:Transcription Factor AP-2 / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001616:beta-Galactosidase / Q000378:metabolism
D020033:Protein Isoforms; D050656:Transcription Factor AP-2; D016159:Tumor Suppressor Protein p53; D008156:Luciferases; D001616:beta-Galactosidase