Mm. Rolls et al., NOVEL INFECTIOUS PARTICLES GENERATED BY EXPRESSION OF THE VESICULAR STOMATITIS-VIRUS GLYCOPROTEIN FROM A SELF-REPLICATING RNA, Cell, 79(3), 1994, pp. 497-506
Self-propagating infectious particles were produced in animal cells tr
ansfected with an RNA replicon encoding a single viral structural prot
ein, the vesicular stomatitis virus glycoprotein (VSV-G). The replicon
is derived from an alphavirus, Semliki Forest virus (SFV), and encode
s the SFV RNA replicase, but none of the SFV structural proteins. Afte
r transfection of the replicon into tissue culture cells, expression o
f G protein spread from small foci throughout the culture. Supernatant
s from the cells contained infectious, virus-like particles that could
be passaged and were neutralized by anti-VSV serum. The majority of t
he infectious particles were smaller and less dense than either VSV or
SFV. Characterization by electron microscopy showed membrane-envelope
d vesicles that contained the VSV-G protein. Infectious particles were
apparently generated by budding of vesicles containing VSV-G protein
and the RNA replicon. These experiments reveal that an enveloped infec
tious agent can be much simpler than previously thought.