Background: The potential of plants, as a safe and eukaryotic system, is considered in the production of recombinant therapeutic human protein today; but the expression level of heterologous proteins is limited by the post-transcriptional gene silencing (PTGS) response in this new technology. The use of viral suppressors of gene silencing can prevent PTGS and improve transient expression level ...

background: the potential of plants as a safe and eukaryotic systems, are considered for producing recombinant therapeutic human protein today; but the expression level of heterologous proteins is limited by the post-transcriptional gene silencing (ptgs) response in this new technology. the use of viral suppressors of gene silencing can prevent ptgs and improve transient expression level of for...

Vascular endothelial growth factor A (VEGFA) is a specific mitogen for vascular endothelial cells that plays a critical role in cancer neoangiogenesis. Here, we report that the nucleolar tumor suppressor p19(ARF) suppresses VEGFA expression, acting at the level of mRNA translation without affecting the transcription of the VEGFA gene. Translational repression of VEGFA mRNA by p19(ARF) does not ...

In plants, posttranscriptional gene silencing (PTGS) is an ancient and effective defense mechanism against viral infection. A number of viruses encode proteins that suppress virus-activated PTGS. The p19 protein of tombusviruses is a potent PTGS suppressor which interferes with the onset of PTGS-generated systemic signaling and is not required for viral replication or for viral movement in Nico...

BACKGROUND In recent years, different HIV antigens have been successfully expressed in plants by either stable transformation or transient expression systems. Among HIV proteins, Nef is considered a promising target for the formulation of a multi-component vaccine due to its implication in the first steps of viral infection. Attempts to express Nef as a single protein product (not fused to a st...

The three-dimensional structure of an siRNA bound to the tombusvirus p19 protein--a suppressor of gene silencing--provides a first glimpse into how plant viruses can defeat their host's anti-viral RNAi defenses.

RNA interference (RNAi) is a key regulator of various biological systems including viral infection. Within a virus life cycle gene products can be modulated by the RNA interference (RNAi) pathway which can crucially impact productive virus replication. Herein we explored the RNA interference suppressor protein P19 derived from a plant virus and we found that P19 enhanced adenovirus replication ...

The gene encoding a novel protein designated nm23-H1, which was recently identified as identical to the A subunit of nucleotide diphosphate kinase from human erythrocytes, has been proposed to play a role in tumor metastasis suppression. We report that untreated neuroblastoma tumors contain a cellular polypeptide (Mr = 19,000) designated p19, identified in two-dimensional electrophoretic gels, ...

Post-transcriptional gene silencing is commonly observed in polyploid species and often poses a major limitation to plant improvement via biotechnology. Five plant viral suppressors of RNA silencing were evaluated for their ability to counteract gene silencing and enhance the expression of the Enhanced Yellow Fluorescent Protein (EYFP) or the β-glucuronidase (GUS) reporter gene in sugarcane, a ...

Tumor suppressor proteins must be exquisitely regulated since they can induce cell death while preventing cancer. For example, the p19 tumor suppressor (p14 in humans) appears to stimulate the apoptotic function of the p53 tumor suppressor to prevent lymphomagenesis and carcinogenesis induced by oncogene overexpression. Here we present a genetic approach to defining the role of p19 in regulatin...