The arenavirus genomic L RNA segment represents approximately 70% of the viral genetic material but current understanding of the organization, regulation, and functioning of the viral L products remains limited. Biological studies with reassortant viruses have implicated the L RNA segment in the lethal infection of adult guinea pigs produced by LCMV-WE but no further explanation of the pathogenic process is presently available. We have initiated a detailed molecular analysis of LCMV L products based on construction and characterization of L-specific cDNA clones and synthesis of L-specific hybridization probes. Nucleotide sequencing studies have allowed the derivation of a partial amino acid sequence for a predicted L protein and antisera raised against synthetic peptides have demonstrated an L protein in Western blotting experiments. Using this approach we have identified a single high molecular weight protein (approximately 200,000 Da) in purified virions and in viral ribonucleoprotein complexes extracted from acutely infected tissue culture cells. This L protein is translated from a nonpolyadenylated, genomic complementary L mRNA and potentially represents part or all of the viral RNA-dependent RNA polymerase.
Bibliographical noteFunding Information:
This is Publication Number 4738-IMM from the Department of Immunology, Research Institute of Scripps Clinic, La Jolla, California 92037. This work was supported in part by USPHS Grants NS-12428 and AG-04342 and DOD contracts DAMD C-3013 and C-6234. The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. We thank Dr. Michael Oldstone for continued interest and support for these studies and Ms. Nicole Nguyen and Mrs. Gay L. Schilling for expert technical and secretarial assistance.