Possible oncogenic potential of DeltaNp73: a newly identified isoform of human p73.
p73, a recently identified gene highly homologous to p53, can transactivate p53 target genes and induce apoptosis. Here we report the identification of an NH(2)-terminal truncated isoform of human p73, DeltaNp73, which is capable of suppressing p53- and p73-dependent transactivation. We speculate that this suppression is achieved by competing for the DNA binding site in the case of p53 and by direct association in the case of TAp73. Expression of DeltaNp73 in cancer cell lines also inhibited suppressive activity of p53 and TAp73 in colony formation, implying possible involvement of DeltaNp73 in oncogenesis by inhibiting the tumor-suppressive function of p53 and TAp73. Also reported is the identification of TAp73eta, a new member of the COOH-terminal truncated isoform of p73 and tissue-specific expression of these isoforms, along with other previously identified p73 isoforms.
Ishimoto
Osamu
O
Department of Cell Biology, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
Kawahara
Chikashi
C
Enjo
Kentaro
K
Obinata
Masuo
M
Nukiwa
Toshihiro
T
Ikawa
Shuntaro
S
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002455:Cell Division / Q000502:physiology; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016147:Genes, Tumor Suppressor; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D020033:Protein Isoforms; D015533:Transcriptional Activation / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors; D025521:Tumor Suppressor Proteins
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human