Practice question

Intrinsic termination, also termed Rho-independent, encoded purely by DNA sequence producing terminator structure in nascent RNA. Sequence comprises GC-rich inverted repeat capable forming stable hairpin stem-loop of 7-20 base pairs followed immediately by run of four to eight uridines that pair weakly with template adenines. Hairpin nucleation within polymerase exit channel causes pausing and allosteric destabilization while weak rU-dA hybrid facilitates transcript release without ATP. Mutations disrupting hairpin stability or replacing U-tract reduce termination efficiency. This architecture widely used for bacterial gene boundaries and engineered expression vectors for efficient transcription cessation.