p73, like Notch, has been implicated in neurodevelopment and in the maintenance of the mature central nervous system. In this study, by the use of reporter-gene assays, we demonstrate that C-promoter binding factor-1 (CBF-1)-dependent gene transcription driven by the Notch-1 intracellular domain (N1(ICD)) is potently antagonized by exogenously expressed transactivating (TA) p73 splice variants in SH-SY5Y neuroblastomas and in primary neurones. Time course analysis indicated that the inhibitory effects of TAp73 are direct and are not mediated via the product of a downstream target gene. We found that endogenous TAp73 stabilized by either c-Abl or cisplatin treatment also potently antagonized N1(ICD)/CBF-1-dependent gene transcription. Furthermore, western blotting revealed that exogenous TAp73 suppressed endogenous hairy and enhancer of split-1 (HES-1) protein levels and antagonized the increase in HES-1 protein induced by exogenous N1(ICD) expression. Evidence of a direct physical interaction between N1(ICD) and TAp73 alpha was demonstrated by co-immunoprecipitation. Using Notch deletion constructs, we demonstrate that TAp73 alpha binds the N1(ICD) in a region C-terminal of aa 2094. Interestingly, Delta Np73 alpha and TAp73 alpha(R292H) also co-purified with N1(ICD), but neither inhibited N1(ICD)/CBF-1-dependent transcription. This suggests that an intact transactivation (TA) domain and the ability to bind DNA are necessary for TAp73 to antagonize Notch signalling. Finally we found that TAp73 alpha reversed the N1(ICD)-mediated repression of retinoic acid-induced differentiation of SH-SY5Y neuroblastomas, providing functional evidence for an inhibitory effect of TAp73 alpha on notch signalling. Collectively, these findings may have ramifications for neurodevelopment, neurodegeneration and oncogenesis.

Hooper, C., Tavassoli, M., Chapple, J.p., Uwanogho, D., Goodyear, R., Melino, G., et al. (2006). TAp73 isoforms antagonize Notch signalling in SH-SY5Y neuroblastomas and in primary neurons. JOURNAL OF NEUROCHEMISTRY, 99(3), 989-999 [10.1111/j.1471-4159.2006.04142.x].

TAp73 isoforms antagonize Notch signalling in SH-SY5Y neuroblastomas and in primary neurons

MELINO, GENNARO;
2006-01-01

Abstract

p73, like Notch, has been implicated in neurodevelopment and in the maintenance of the mature central nervous system. In this study, by the use of reporter-gene assays, we demonstrate that C-promoter binding factor-1 (CBF-1)-dependent gene transcription driven by the Notch-1 intracellular domain (N1(ICD)) is potently antagonized by exogenously expressed transactivating (TA) p73 splice variants in SH-SY5Y neuroblastomas and in primary neurones. Time course analysis indicated that the inhibitory effects of TAp73 are direct and are not mediated via the product of a downstream target gene. We found that endogenous TAp73 stabilized by either c-Abl or cisplatin treatment also potently antagonized N1(ICD)/CBF-1-dependent gene transcription. Furthermore, western blotting revealed that exogenous TAp73 suppressed endogenous hairy and enhancer of split-1 (HES-1) protein levels and antagonized the increase in HES-1 protein induced by exogenous N1(ICD) expression. Evidence of a direct physical interaction between N1(ICD) and TAp73 alpha was demonstrated by co-immunoprecipitation. Using Notch deletion constructs, we demonstrate that TAp73 alpha binds the N1(ICD) in a region C-terminal of aa 2094. Interestingly, Delta Np73 alpha and TAp73 alpha(R292H) also co-purified with N1(ICD), but neither inhibited N1(ICD)/CBF-1-dependent transcription. This suggests that an intact transactivation (TA) domain and the ability to bind DNA are necessary for TAp73 to antagonize Notch signalling. Finally we found that TAp73 alpha reversed the N1(ICD)-mediated repression of retinoic acid-induced differentiation of SH-SY5Y neuroblastomas, providing functional evidence for an inhibitory effect of TAp73 alpha on notch signalling. Collectively, these findings may have ramifications for neurodevelopment, neurodegeneration and oncogenesis.
2006
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/11 - BIOLOGIA MOLECOLARE
English
Con Impact Factor ISI
Development; Neurodegeneration; Notch; Oncogenesis; p53; p73
Hooper, C., Tavassoli, M., Chapple, J.p., Uwanogho, D., Goodyear, R., Melino, G., et al. (2006). TAp73 isoforms antagonize Notch signalling in SH-SY5Y neuroblastomas and in primary neurons. JOURNAL OF NEUROCHEMISTRY, 99(3), 989-999 [10.1111/j.1471-4159.2006.04142.x].
Hooper, C; Tavassoli, M; Chapple, Jp; Uwanogho, D; Goodyear, R; Melino, G; Lovestone, S; Killick, R
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/40236
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