In bacteria, production of aberrant RNAs and transcription of foreign genes, including those on phages, are readily terminated by a hexameric ATPase, Rho. However, to make necessary transcripts, particularly during stress, bacteria depend on mechanisms to temper Rho activity. Similarly, phages have evolved diverse Rho-inhibitory mechanisms to enable the expression of their own genomes. In recent years, the structural bases of many such anti-termination mechanisms have been elucidated.
