Abstract
Poly(adenylic acid) sequences have been isolated from the Gram-negative bacterium Caulobacter crescentus. Most of these A-rich tracts are associated with large RNA molecules that constitute an important fraction of the unstable RNA in these bacteria, and, as estimated by poly(U) filter binding, they are not present in the 16S or 23S ribosomal RNA. Preliminary estimates of size from polyacrylamide gel electrophoresis suggest that the majority of the A-rich tracts ranges from 15 to approximately 50 residues in length.