PARTIAL RECONSTITUTION OF TOBACCO MOSAIC VIRUS

TMV reconstitutes rapidly in vitro at 24°; a yield of 30% was obtained after 30 min of reconstitution. The maximum yield was around 60%, reached after 7 hours. Electron micrographs of reconstituted TMV suspensions show particles of predominant lengths 700 Å and 3000 Å. The two populations were separated by rate zonal centrifugation on a linear sucrose gradient: the bottom zone contained infective 3000 Å particles; the top zone contained whole infective RNA molecules partially coated to form a nucleoprotein of mean length 700 Å. These incompletely coated particles were able to produce infective 3000 Å particles when they were mixed with native viral protein. These results support a polar reconstitution. © 1969.