Binding of adenovirus VA RNA to mRNA: a possible role in splicing?

Most, though not all, of the messenger RNAs of higher cells are composed of transcripts from two or more non-contiguous DNA segments that are 'spliced' together by mechanisms which are poorly understood. There has been recent speculation that small RNA molecules may play a part in the splicing reaction, acting as templates or adaptors to stabilize the appropriate conformation of a precursor RNA. Adenovirus-2 codes for two low molecular weight RNAs, the virus-associate (VA) RNAs I and II, major and minor species, respectively. These RNAs are about 160 nucleotides long and have both been sequenced. They originate from closely spaced genes which are transcribed by RNA polymerase III, but have not been definitively associated with any function. We have shown previously that a fraction of the VA RNA of infected cells is complexed with high molecular weight RNA in a denaturation-sensitive fashion. Results presented here show that the VA RNAs bind to unfractionated late virus mRNA and to a cloned copy of a single mRNA species, but not to corresponding cloned segments of viral genomic DNA. It is suggested that VA RNA may act as a template in the splicing reaction.