Characterization of Subviral Components Resulting from Treatment of Rabies Virus with Tri(n-butyl) Phosphate

The PM strain of rabies virus was grown in human diploid WI-38 cells and labelled with the following radioactive substances: [14C]- or pH]-d-glucosamine, [14C]-uridine, [l~C]-stearic a id, [aH]-choline and a mixture of [l~C]-amino acids. It was then purified and treated with o.I ~o tri(n-butyl)phosphate (TNBP) in the presence of o. r % Tween 80. All the stearic acid and choline and about 82 ~o and 40 °/o, re-spectively, of the d-glucosamine and amino acid (but none of the uridine) label was released from the virus. It was concluded that TNBP dissociates the lipids, most of the glycoproteins, and small quantities of non-glycosylated proteins from the virus leaving behind particles containing all of the virus RNA. These particles edi-mented in sucrose gradients at the same rate as did intact virus; they had a higher buoyant density in CsC1 gradients (~.3o4 compared with 1.244 g./cm3.) and they re-sembled intact virus in overall size and shape but lacked most of the surface projec-tions. By polyacrylamide g l electrophoresis the following polypeptide species were identified in intact particles (tentative molecular weights are given in paren-theses): glycoproteins GP I (78,0o0) and GP 2 (65,000) ; nucleocapsid proteins NP I (58,ooo) and NP2 (47,000) and two additional proteins MP (35,ooo) and CP (22,000). Treatment with TNBP released nearly all GPI and GP2 and small quantities of MP. Particles obtained by treatment of the virus with the proteolytic enzyme bromelain also lacked the surface projections (and the glycoproteins GP i and GP2) but retained the lipids