We propose to develop genetic approaches to the study of ribosomal RNA in E. coli. The main feature of the method is to use antibiotic-resistance mutations in 16S and 23S rRNA as genetic markers. Another important aspect is the use of rapid methodologies that will permit isolation and characterization of large numbers (hundreds) of mutants. Mutations that confer a variety of phenotypes, including temperature-sensitive, "downs," nulls, Ram, suppressors, etc. will be isolated and localized by marker rescue and DNA sequencing. Second site revertants will also be sought, in an effort to identify long- range structural and functional interactions involving ribosomal RNA.
