Unusual in vivo turnover of transfer RNA in Vibrio cholerae

Two lines of evidence suggest that, unlike in other organisms, the transfer RNAs of Vibrio cholerae undergo rapid turnover in vivo. Firstly, the tRNA content of V. cholerae cells treated with rifampicin (an inhibitor of initiation of RNA synthesis) decreased rapidly and continuously. Secondly, the newly synthesized tRNAs were rapidly degraded even under normal conditions of growth; the average half life of tRNA was 11.8 min. The degradation is mediated by an enzyme(s), present in V. cholerae cytoplasm, that apparently degrades tRNA completely. Rapid turnover is balanced by an enhanced rate of tRNA biogenesis, which was calculated to be 2.5 times higher than that in Escherichia coli.