Replication of a Nodavirus in C. elegans

The 'Flock House' nodavirus was isolated from the New Zealand grass grub at the Flock House agricultural experiment station near Bulls, New Zealand. In collaboration with the laboratory of Shou-Wei Ding in Plant Pathology at UCR, we are studying aspects of FHV replication using the nematode C. elegans as a model for viral pathogen-host interactions.

During infection, viral RNAs are translated by the host to produce two proteins: RdRP (RNA-dependent RNA polymerase) and the capsid protein precursor. The RdRP will make (-), then (+)-strand copies of RNA1 and RNA2 for packaging into virus particles. The dsRNA intermediates created during replication are substrates for RNA-mediated interference (RNAi). A subgenomic RNA (RNA3) is produced by the RdRP, primed from within the (-) copy of RNA1. RNA3 encodes B2, a protein that can block RNA interference in plants and animals.

Replication of FHV can be demonstrated by introducing RNA1 into cells directly, by causing its expression from a DNA transgene. Accumulation of RNA3 becomes a simple marker for successful replication: RNA3 will accumulate to high levels after RNA1 is translated into the RdRP, and if the RNAi machinery of the host has been efficiently blocked by the B2 protein.

The Ding lab and our lab have published a paper in Nature on our findings:

Lu, R., Maduro, M., Li, F., Li, H.W., Broitman-Maduro, G., Li, W.X., and Ding, S.W. (2005). Animal virus replication and RNAi-mediated antiviral silencing in Caenorhabditis elegans. Nature 436, 1040-1043. Abstract

Replication of FHV and suppression of RNAi in plant and animal cells (Li et al., 2002)
FHV structure (1) FHV Structure (2)