Rho-independent transcription termination

Rho-independent transcription termination is a mechanism in bacteria whereby mRNA transcription is stopped. In this mechanism, the mRNA contains a stem-loop followed by several Us (uracil residues), which destabilizes the RNA polymerase binding to the DNA template strand, causing transcription to stop. Stems are typically 5-8 base pairs long, with 4 or more Us. However, terminators with longer stems can tolerate fewer Us. Rho-independent transcription termination is a frequent mechanism underlying the activity of cis-acting RNA regulatory elements, such as riboswitches.