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...

The internal structural proteins of avian sarcoma and leukemia viruses are derived from a precursor polypeptide that is the product of the viral gag gene. The N-terminal domain of the precursor gives rise to p19, a protein that interacts with the lipid envelope of the virus and that may also interact with viral RNA. The C terminus of p19 from the Prague C strain of Rous sarcoma virus was previo...

The INK4a/ARF locus encodes two different proteins involved in cell cycle control. Both molecules, p16(INK4a) and p19(ARF), inhibit cell cycle progression and have been shown to act as tumor suppressors in a variety of models. Their expression is controlled by separate promoters responding to different stimuli and they therefore show independent transcriptional regulation. We have cloned and ch...

Protein P19 encoded by the conjugative resistance plasmid R1 has been identified as being one member of a large family of muramidases encoded by bacteriophages and by type III and type IV secretion systems. We carried out a mutational analysis to investigate the function of protein P19 and used in vivo complementation assays to test those of several P19 mutants. The results indicated that conse...

The P19 protein of Tomato bushy stunt virus is a potent suppressor of RNA silencing and, depending on the host species, is required for short- and long-distance virus movement and symptom production. P19 interacts with plant ALY proteins and relocalizes a subset of these proteins from the nucleus to the cytoplasm. Here we showed that coexpression by agroinfiltration in Nicotiana benthamiana of ...

The jun and fos gene families encode DNA binding proteins involved in transcriptional regulation of genes containing a TPA responsive element (TRE). To study their role in gene regulation during early mammalian development, expression and transcription regulatory properties of their gene products were investigated during retinoic acid (RA) induced differentiation of P19 embryonal carcinoma (EC)...

Little is known about the mechanisms underlying the effects of Cyclosporin A (CsA) on the fate of stem cells, including cardiomyogenic differentiation. Therefore, we investigated the effects and the molecular mechanisms behind the actions of CsA on cell lineage determination of P19 cells. CsA induced cardiomyocyte-specific differentiation of P19 cells, with the highest efficiency at a concentra...

Studies of mammalian RNA interference (RNAi) have focused largely on the actions of microRNAs; however, in other organisms, endogenous short-interfering RNAs (siRNAs) are involved in silencing processes. To date, similar molecules have been difficult to characterize in mammalian cells. P19 is a plant suppressor of RNA silencing that binds with high affinity to siRNAs. Here, the short RNAs bound...

Our objective was to develop a suitable cardiomyocyte progenitor cell line for use in testing biomaterials as potential scaffolds in cardiac tissue engineering. We transfected P19 cells with the human cardiac -actin promoter driving the gene for puromycin resistance, to create a stable cardiomyocyte-selectable P19 cell line, termed P19(CAPuro). Puromycin selection resulted in a 4-10 fold enrich...

DNA methylation is an important mechanism of gene silencing in mammals catalyzed by a group of DNA methyltransferases including Dnmt1, Dnmt3a, and Dnmt3b which are required for the establishment of genomic methylation patterns during development and differentiation. In this report, we studied the role of DNA methyltransferases during retinoic acid induced neuronal differentiation of P19 cells. ...