Induction of apoptosis by the p53-related p73 and partial inhibition by the baculovirus-encoded p35 in neuronal cells.
To better understand whether the p53-related p73 gene could induce neuronal apoptosis, we tested whether p73 induced cell killing in three neuronal cell lines and whether apoptosis could be inhibited by p35, a baculovirus-encoded protein that blocks caspase 3. Recombinant adenoviruses carrying the hemagglutinin (HA)-tagged p73beta or p35, or the green fluorescent protein gene driven by the cytomegalovirus immediate-early promoter were constructed, and used to infect human SK-N-AS and SK-N-SH neuroblastoma, and rat PC12 pheochromocytoma cells. Infection with Adp73beta virus resulted in p73beta over-expression and substantial reduction of cell viability due to apoptosis in all three neuronal cell lines as compared with the control AdGFP virus. These results indicate that p73beta over-expression in neuronal cells could induce apoptotic cell death regardless of the endogenous expression of p73. The p73 effect was partially blocked by co-expression of the wild-type p35, suggesting caspase-mediated cell killing. Insertion of a hemagglutinin (HA) tag at the N-terminus of p35 markedly reduced its ability to inhibit the p73 effect compared with the wild-type p35, while insertion of an HA tag to the C-terminus of p35 had no appreciable effect. Taken together, our results suggest that the N-terminal structure of p35 is critical for its anti-apoptotic activity on p73-induced apoptosis in neuronal cells.
Lo
Warren D
WD
Department of Pediatrics, Children's Hospital, The Ohio State University, Columbus, USA.
Akhmametyeva
Elena M
EM
Zhu
Lingyun
L
Friesen
Paul D
PD
Chang
Long-Sheng
LS
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D016147:Genes, Tumor Suppressor; D005822:Genetic Vectors; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D009474:Neurons / Q000378:metabolism* / Q000821:virology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics; D051381:Rats; D014407:Tumor Cells, Cultured; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D051034:Inhibitor of Apoptosis Proteins; D009687:Nuclear Proteins; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D014764:Viral Proteins; C086430:inhibitor of apoptosis, Nucleopolyhedrovirus; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases