- Volume 65, Issue 3, 1984

Monoclonal antibodies 35S and 55S, specific for herpes simplex virus type 1 (HSV-1) glycoproteins gB and gD respectively, were found to react with infected cell membranes but not cell-free virions. This indicates that the spectrum of viral determinants detectable on the infected cell surface is not identical to that detectable on the virion envelope. The monoclonal antibody 35S could promote recovery from ocular HSV-1 infection in mice. Thus, antibody reactive with infective cell-specific determinants can play a significant role in host resistance to HSV-1 infection.

Soluble transcriptase containing the L and the NS proteins was isolated from purified vesicular stomatitis virus and its binding with the template ribonucleoprotein containing the N protein-RNA complex was studied with respect to its ability to initiate and synthesize RNA in vitro. By using u.v.-irradiated template reconstituted with soluble transcriptase, it was shown that the synthesis of leader RNA and other small initiated mRNA sequences continued while full-length mRNA synthesis decreased by 90%. In the presence of ATP and CTP, the reconstituted complex synthesized polyphosphorylated oligonucleotides which include AC, AAC and AACA which represent 5′-terminal sequences transcribed from the leader template and genes coding for mRNAs. In the presence of arabinosyl ATP, an inhibitor of RNA synthesis in vitro, the synthesis of leader RNA was found to be inhibited considerably more than other small initiated mRNA sequences. Reconstitution of RNA synthesis with soluble transcriptase and template in the presence of viral matrix (M) protein at low ionic condition resulted in virtual cessation of leader RNA synthesis, although the synthesis of small initiated N mRNA, 11 to 14 bases, continued. These results suggest that transcriptase can bind at multiple sites on the genome template and initiate RNA chains.

An RNA-dependent polymerase associated with rice gall dwarf virus (RGDV), a new Phytoreovirus, was characterized. Optimum polymerase activity was found between pH 8.0 and 8.5 at 25°C. Mg2+ was essential for the activity, the optimum concentration being 2 mm. Mn2+ could replace Mg2+. The RNA products synthesized in vitro hybridized with RGDV RNA, but not with RNA of rice dwarf virus which is in the same subgroup of plant reoviruses. Electrophoretic analysis of the products showed at least nine bands, the sizes of which are discussed.

Satellite RNAs of CARNAs 5s (cucumber mosaic virus-associated RNA 5s) emerged in serial passage lines of Spanish cucumber mosaic virus isolates established in Chenopodium, squash and two tobacco varieties. No satellite was detected in virus obtained from tomato serial passage lines. The satellites were identified by their biological effect on tomato, by their gel electrophoretic mobility and by nucleic acid hybridization, as being very similar in sequence to known CARNA 5s. Interactions among host, virus and CARNA 5 affect the selection of a particular CARNA 5 variant.