The structure and activity of the Rho protein is similar to that of the F1 subunit of ATP synthase, supporting the theory that the two share an evolutionary link.
[4] Rho factor is widely present in different bacterial sequences and is responsible for the genetic polarity in E. coli.
[6] The process of termination by Rho factor is regulated by attenuation and antitermination mechanisms, competing with elongation factors for overlapping utilization sites (ruts and nuts), and depends on how fast Rho can move during the transcription to catch up with the RNA polymerase and activate the termination process.
The newly synthesised ribonucleotides are removed one at a time by the cleavage factors CSTF and CPSF, in a process that is still not fully understood.
RNA polymerase III terminates after a series of uracil polymerization residues in the transcribed mRNA.