“…It appears that in the CMV plus satellite RNA system specific mechanisms have evolved for the replication and regulation of RNA components. The satellite RNA cannot replicate in the absence of CMV genomic RNAs in whole plants or isolated protoplasts (23), it shows a varying degree of specificity to various strains (24), it specifically reduces the level of RNA 1 and 2 synthesis (24), it has a small "anti-sense" sequence to a conserved region of RNA 1 and 2 (1), it forms a similar hairpin structure at the 5'-end as the structure in RNA 1 and 2 (1), it has a partial 3'-terminal homology to CMV genomal RNAs (7) and, finally, it specifically binds to the coat protein gene (Fig. 4B).…”