Robert Touitou

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The cyclin-dependent kinase inhibitor p21WAF1/CIP1 is a key regulator of cell-cycle progression and its expression is tightly regulated at the level of transcription and by proteasome-dependent proteolysis. The turnover of p21WAF1/CIP1 by proteasomes does not always require the ubiquitylation of p21WAF1/CIP1 suggesting that there could be an alternative(More)
EBNA3C can specifically repress the expression of reporter plasmids containing EBV Cp latency-associated promoter elements. Cp is normally the main promoter for EBNA mRNA initiation, so it appears that EBNA3C contributes to a negative autoregulatory control loop. By mutational analysis it was previously established that this repression is consistent with(More)
CtBP has been shown to be a highly conserved corepressor of transcription. E1A and all the various transcription factors to which CtBP binds contain a conserved PLDLS CtBP-interacting domain, and EBNA3C includes a PLDLS motif (amino acids [aa] 728 to 732). Here we show that EBNA3C binds to CtBP both in vitro and in vivo and that the interaction requires an(More)
Inactivation of retinoblastoma protein (Rb) plays a critical role in the development of human malignancies. It has been shown that Rb is degraded through a proteasome-dependent pathway, yet the mechanism is largely unclear. MDM2 is frequently found amplified and overexpressed in a variety of human tumors. In this study, we find that MDM2 promotes Rb(More)
Expression of EBNA3C is essential for the immortalization of B cells by EBV in vitro and, in co-operation with activated ras, EBNA3C has oncogenic activity in primary rodent fibroblasts. This suggested that this viral oncoprotein might disrupt the cyclin/CDK-pRb-E2F pathway, which regulates cell cycle progression at the restriction point (R-point) in G1 of(More)
A yeast two-hybrid screen using EBNA3C as bait revealed an interaction between this Epstein-Barr virus (EBV)-encoded nuclear protein and the C8 (alpha7) subunit of the human 20S proteasome. The interaction was confirmed by glutathione S-transferase (GST) pull-down experiments and these also revealed that the related proteins EBNA3A and EBNA3B can bind(More)
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