Regulation of gene expression in bacteria by cis-acting RNA elements can be investigated both in vivo and in vitro. Analyses in vivo can focus on changes in mRNA transcript levels or in protein production. Systems that are regulated at the level of premature termination of transcription are best analyzed by monitoring expression of a fusion to an easily assayable reporter gene construct or by direct measurement of the terminated and readthrough transcripts. These experimental approaches are described in the context of theBacillus subtilisT box mechanism, which responds to uncharged tRNA as the effector, and are readily adaptable to other regulatory systems that respond to other signal molecules, and other experimental systems.
