The effect of multiple dispersed copies of the origin-of-assembly sequence from TMV RNA on the morphology of pseudovirus particles assembled in vitro.

Supercoiled plasmid DNA was used as a template to transcribe long concatameric RNA molecules containing several dispersed copies of the origin-of-assembly sequence (OAS) from tobacco mosaic virus (TMV) RNA. When incubated with TMV coat protein "disks" in vitro, these RNAs spontaneously assembled into TMV-like pseudovirus particles. However, as each OAS initiated assembly more or less simultaneously, the concatameric RNA species generated complex nucleoprotein structures of predictable morphology. Similar structures were proposed some time ago (M. E. Taliansky, I. B. Kaplan, L. V. Yarvekulg, T. I. Atabekova, A. A. Agranovsky, and J. G. Atabekov, 1982, Virology 118, 309-316) to account for the RNase-sensitive phenotype of a ts mutant of TMV, Ni2519. These results extend the utility of our RNA-packaging vector system and confirm many of the predictions based on the current model for the self-assembly of TMV.