Practice question

Rho-dependent termination requires specific cis-acting RNA element termed Rho utilization site, rut site, located upstream of termination point within nascent transcript. Rut characterized as cytosine-rich, guanosine-poor, unstructured stretch approximately 80 nucleotides lacking stable stem-loops allowing Rho hexamer loading. After binding, Rho hydrolyzes ATP translocating along RNA catching polymerase paused at downstream region rich in GC sequences. Essentiality distinguishes this mechanism from intrinsic termination which needs hairpin plus polyU tract and operates without Rho. Deletion or structure sequestration of rut abolishes termination highlighting requirement.