Talk abstracts

Talk on Saturday 11:40-12:00pm submitted by Peter Nagy

Role of Viral RNA as an Assembly Platform for the Tombusvirus Replicase Complex

Peter Nagy (Plant Pathology, University of Kentucky), Judit Pogany (Plant Pathology, University of Kentucky), Kunj Pathak (Plant Pathology, University of Kentucky)

Abstract:
Many viruses of plants use RNA as a genetic material, allowing for studies on template function of RNA. The viral RNA contains cis-acting regulatory sequences to control RNA synthesis. RNA replication in the virus-infected cells is performed via assembly of a specialized viral RNA-protein complex, named viral replicase complex. To study the assembly of the functional replicase complex (RC) for Tomato bushy stunt virus (TBSV), a small model plant virus, we expressed His6-tagged p33 and p92pol replication proteins and a TBSV replicon RNA in yeast, a model host. Affinity-based purification of the replicase complex from solubilized yeast membrane fractions was used to obtain functional replicase preparations. Based on in vitro replicase assays with added RNA templates, we found that three short cis-acting elements had to be present in the expressed viral RNA for the assembly of the viral RC. These were the p33 recognition element (p33RE), a replication promoter (gPR) and a replication silencer element (RSE). Detailed analysis of the role of these sequences revealed that long-range interaction might be important for the assembly of the RC. Building on our recent data, the most current model on the assembly of the tombusvirus RC will be discussed.

References:
1. Pogany, J., Fabian, M., White, K.A., and Nagy, P. D. 2003. A replication silencer element in an RNA virus. EMBO Journal 22: 5602-5611.

2. Panaviene, Z., Panavas, T., and P. D Nagy. 2005. Role of an internal and two 3\'-termi

Keywords: viral RNA, RNA-protein interaction, secondary structure