TABLE 3.

Relative levels of tmRNA produced in ssrA mutant strains

Strain	ssrA allele	Location of relevant ssrA allele	Relative tmRNA levela
K37	ssrA+	Normal site	1.0
K8619	ssrA::cat	Normal site	NDb
K8664	ssrA+	λatt	7.5
K8637	ssrAO	λatt	1.4
K8666	ssrADD	λatt	0.5
K8668	ssrA::cat	Normal site	ND
K8810	ssrAGA	Plasmid	12.5
K8812	ssrAGC	Plasmid	1.9
K8814	ssrAUG	Plasmid	6.4
K8895	ssrACG	Plasmid	6.1

^aThe ratio of tmRNA to 16S rRNA measured for the wild-type strain, K37, was set equal to 1, and the tmRNA/16S rRNA ratios measured in the other strains were normalized to this value. 

^bND, not detectable.