2 DISTINCT POPULATIONS OF VESICULAR STOMATITIS-VIRUS RIBONUCLEOPROTEIN CORES WITH DIFFERENTIAL SENSITIVITIES TO MICROCOCCAL NUCLEASE

Purified vesicular stomatitis virus was disrupted with Triton N101 and treated with micrococcal nuclease. The genome RNA (42S) within the ribonucleoprotein (RNP) core contained nuclease-sensitive sites. At least 60% of the genome RNA sedimented around the 31S region following nuclease treatment; the rest was totally resistant. Transcriptase activities and synthesis of viral mRNA by the nuclease-treated or untreated virions were identical. Sites of the nuclease action appeared around the center of the genome RNA. The 3''-terminal promotor region of the genome RNA within the RNP core was inaccessible to the nuclease action after removal of the L and the NS proteins from it. The structure and function of the RNP core are discussed.