TABLE 1.
Effect on replication of mutations in the 5′- and 3′-terminal dinucleotides of KUN replicon RNA
| RNA | Sequencea
|
% RNA replication ofb:
|
||
|---|---|---|---|---|
| 5′-RNA positive strand-3′ | RNA negative strand-3′ | 45 h | 69 h | |
| Wild type | 5′AGU-UCUOH3′ | ACUOH3′ | 100 | NA |
| 3′-terminal mutations | 5′AGU-UuUOH3′ | 0 | 0 | |
| -UgUOH3′ | 0 | 0 | ||
| -UaUOH3′ | 0 | 0 | ||
| 5′AGU-UCgOH3′ | 70 | 70 | ||
| -UCaOH3′ | 60 | 70 | ||
| -UCcOH3′ | 40 | 70 | ||
| 5′-terminal mutations | 5′uGU | ACaOH3′ | 0 | |
| 5′gGUc | ACcOH3′ | 0 | ||
| 5′AaU | AuUOH3′ | 0 | ||
| 5′AuUc | AaUOH3′ | 0 | ||
a
Terminal dinucleotides are shown in boldface, and the mutated nucleotides are shown in lowercase.
b
RNA replication by the replicons with 3′-terminal mutations was quantified as a percentage of that of wild-type replicon RNA at 45 h by densitometry of the autoradiograms used in the Northern blot analysis shown in Fig. 2. NA, no assay done for wild-type RNA.
c
Using the more sensitive RNase protection assay, RNA negative strands copied from these 5′-mutated RNAs transcribed by cellular RNA polymerase from transfected plasmid DNAs were detected (Fig. 3B).