A while ago Lee Ann Weinstein-Schein in my lab found a collection of small RNAs
associated with killer virions and agarose gel purified dsRNA from those
virions. 2-D electrophoretic isolation followed by sequence analysis revealed
these to be tRNAs and 5S RNA (at least all of the ones that we sequenced). At
the time, we were a bit surprised that none seemed to be sequence related to
the viruses, suggesting that they did not originate as transcriptional "pause
products" that were previously described by Bruenn in vitro. It is also
noteworthy that no such association of these RNAs with rRNA purified on the
same agarose gels was seen. We do not know if the small RNAs have any
function in the virions, or are simply associated incidentally or
artefactually. But they are quite reproducible. My own suspicion is that they
get packaged along with viral RNA during replication.
The reference is:
L. A. Weinstein and M. J. Leibowitz. 5S and tRNA-like molecules are associated
with killer virus dsRNA of yeast. J. Gen. Virol. 67: 191-195 (1986).
UMDNJ-RW Johnson Medical School