Saint Louis encephalitis viral ribonucleic acid replication complex.

Pulse-labeled Saint Louis encephalitis viral ribonucleic acid (RNA) is found in the cytoplasm of infected cells associated with a membranous structure which sediments with an average value of 250S. The integrity of the complex is destroyed by detergents and ribonuclease; however, it is stable in ethylenediaminetetraacetic acid (EDTA) which differentiates this structure from cellular polyribosomes. With cultures in which cellular RNA was highly labeled prior to infection, ribosomal RNA could not be demonstrated in the complex isolated from EDTA-sucrose gradients. Single-stranded 43S and the 26S and 20S forms of viral RNA were found in the complex. Viral RNA polymerase activity in sucrose-gradient fractions sedimented in the same region as the fractions which contained the pulse-labeled viral RNA. The polymerase incorporated (3)H-guanosine triphosphate into acid-precipitable material in the absence of added template. It was also found that the replication complex contains viral-specific proteins.