Matrix protein of rabies virus is responsible for the assembly and budding of bullet-shaped particles and interacts with the transmembrane spike glycoprotein G.
To elucidate the functions of rhabdovirus matrix (M) protein, we determined the localization of M in rabies virus (RV) and analyzed the properties of an M-deficient RV mutant. We provide evidence that M completely covers the ribonucleoprotein (RNP) coil and keeps it in a condensed form. As determined by cosedimentation experiments, not only the M-RNP complex but also M alone was found to interact specifically with the glycoprotein G. In contrast, an interaction of G with the nucleoprotein N or M-less RNP was not observed. In the absence of M, infectious particles were mainly cell associated and the yield of cell-free infectious virus was reduced by as much as 500,000-fold, demonstrating the crucial role of M in virus budding. Supernatants from cells infected with the M-deficient RV did not contain the typical bullet-shaped rhabdovirus particles but instead contained long, rod-shaped virions, demonstrating severe impairment of the virus formation process. Complementation with M protein expressed from plasmids rescued rhabdovirus formation. These results demonstrate the pivotal role of M protein in condensing and targeting the RNP to the plasma membrane as well as in incorporation of G protein into budding virions.
Mebatsion
T
T
Department of Clinical Virology, Federal Research Centre for Virus Diseases of Animals, D-72076 Tübingen, Germany.
Weiland
F
F
Conzelmann
K K
KK
D000956:Antigens, Viral; D002459:Cell Fusion; D006023:Glycoproteins / Q000502:physiology*; D008051:Lipid Bilayers; D011820:Rabies virus / Q000502:physiology*; D012261:Ribonucleoproteins / Q000502:physiology; D014759:Viral Envelope Proteins / Q000502:physiology*; D014763:Viral Matrix Proteins / Q000502:physiology*; D019065:Virus Assembly
D000956:Antigens, Viral; D006023:Glycoproteins; D008051:Lipid Bilayers; D012261:Ribonucleoproteins; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; C064951:glycoprotein G, Rabies virus