An E-coli 5S rRNA deletion mutant useful for the study of 5S rRNA structure/function relationships

We report on the construction of a novel strain of E. coli that can be usef ul for studies on the structure/function relationship of 5S rRNAs. The bact erial strain is deficient in six of the eight naturally occurring 5S rRNA g enes (operons B, D, H, G, E) and demonstrates a greatly reduced growth rate that can be compensated by the plasmid-encoded expression of 5S rRNA. The relatively large difference in growth rate between compensated and non-comp ensated mutants provides the basis for a quick and simple assaying system f or both the evaluation and mass screening of divergent 5S rRNA sequences fo r function. We describe the construction of the 5S rRNA deletion mutant BDH GE and characterize the usefulness and limitations of the system for evalua ting structure/function relationships of 5S rRNA sequence.