Expression of foreign rRNA in Δ7 prrn strains.
(A) Primer extension analysis. 23S rRNA molecules in the
rrn+ strain and in Δ7 prrn strains
carrying either E. coli (pSTL102) or S.
typhimurium (pSt1-Km) rRNA plasmid were analyzed by primer
extension as described in Fig. 4. The primer used in this experiment
hybridizes to a common sequence in E. coli and S.
typhimurium 23S rRNAs but gives different extension products
because of a sequence difference between the two molecules.
(B) Fragmentation of 23S rRNA. Total cellular RNA prepared
from the rrn+ strain and Δ7 prrn strains
carrying plasmids with E. coli (Ec,
pSTL102), S. typhimurium (St, pSt1-Km),
or P. vulgaris (Pv, pPM2) rRNA is shown.
Fragmented 23S rRNA molecules are indicated by a prime.