Double-stranded RNA multimers of cucumber mosaic virus (CMV) satellite
RNA were detected in CMV-infected plants. RT-PCR showed that plus-sen
se and minus-sense monomers and plus-sense multimers of satellite RNA
were present. Multimeric minus-sense RNA was not present except in the
form of multimeric dsRNA. Sequence analysis of 52 cloned junction reg
ions in head-to-tail repeats of unit-length satellite RNA indicated th
at about 35% of the junction sequences were precise fusions of monomer
units, 56% lacked sequence of the 5' component, and 10% lacked sequen
ce of both 3' and 5' components. No junction contained additional nucl
eotides. Deletions at the junction regions may have accumulated during
CMV multiplication in inoculated plants. These data suggest that repl
icase is not released from the template during synthesis of multimeric
molecules of satellite RNA.