Arenavirus virion structure and genome organization. Arenaviruses are enveloped viruses with a bisegmented negative strand RNA genome. Each genome segment uses an ambisense-coding strategy to direct the synthesis of two viral polypeptides. The S (ca 3.5 kb) segment encodes for the viral nucleoprotein (NP) and glycoprotein precursor (GPC). GPC is posttranslational processed by the cellular protease S1P into the mature virion surface GP1 and GP2. The L (ca 7.3 kb) segment encodes for the virus RNA-dependent RNA polymerase (L) and a small RING finger protein (Z) that is functionally the arenavirus counterpart of the matrix (M) protein found in many enveloped negative strand RNA viruses. IGR, noncoding intergenic region.
