اسرا سالاری

RNA silencing is an evolutionarily conserved surveillance system. In plants, RNA silencing acts as an antiviral system. Thus, virus infection requires suppression of gene silencing. p19 of Tombusvirus inhibits RNA silencing via its small RNAbinding activity. During Tombusvirus infection, the p19mediated sequestration of siRNAs in virusinfected cells blocks the spread of the mobile, systemic signal of RNA silencing. In this study, some of the characterizations bioinformatics these gene evaluated. Genomatix program determined nucleotide composition and showed that p19 has the highest percentage in adenine plus thymine (53.2%). Total number of negatively charged residues (Asp + Glu) was 25 and total number of positively charged residues (Arg + Lys) was 20. Also Smart program was used to determine the protein domains and it was found one domain (1R9F_A). The results of analysis of Protparam program showed that Glu, Gly and Ser amino acids are most abundant (9.9, 9.9 and 11 respectively %). Isoelectric point is 5.30 and half-life measured 30 hours in mammalian cells. Mega5.0 software was used to investigate the evolutionary relationships this virus with some tombusvirus species. Results showed most closely corresponding with carnation Italian ringspot virus. P19 promotor analysis by using NSITE program found 5 Motif, that high number of motifs are causing the high expression of this gene in virus. Prediction of two-dimensional structures of protein done by Psipred programs. Result showed 4 α helix and 2 beta sheet. This study information can be helpful in vector selection and efficient systems for expression P19 gene.