Synthesis of Tacaribe viral proteins

Abstract

The synthesis of Tacaribe virus-specific proteins in infected BHK-21 cells has been analyzed by polyacrylamide slab gel electrophoresis and fluorography. The two major structural polypeptides of the virion were observed above the host cell background by pulse labeling with amino acid or sugar precursors. In addition to the virion glycoprotein (G), another major virus-specific glycoprotein (MW = 70,000) was detected in infected cells. The nucleoprotein (N) was first detected in infected cells around 24–34 hr postinfection (pi). It appeared to be synthesized as a primary gene product, since no larger precursor was detected by short pulse labeling. The rate of synthesis of N increased until 48 hr pi followed by a slight decrease by 72 hr pi. The structural and nonstructural glycoproteins were detected around 48 hr pi and their rate of synthesis increased up to 60 hr pi. The nucleocapsid protein, the minor nonglycosylated virion protein (P), as well as the structural and nonstructural glycoprotein could be specifically precipitated from infected cells using serum from rabbits hyperimmunized with Tacaribe virions. These results as well as pulse-chase experiments experiments suggest that the nonstructural glycoprotein may be a precursor of the virion glycoprotein.