Question

Synthesis of mRNA molecule is terminated by which of the following factor?

• A. $\alpha$ (alpha)
• B. $\beta$ (beta)
• C. $\sigma$ (sigma)
• D. $\rho$ (rho)

Answer 1

The correct option is D $\rho$ (rho)

• RNA polymerase is a holoenzyme that has five subunits in its core structure. $\alpha$ and $\beta$ subunits are part of the core enzyme.
• $\sigma$ is the sixth subunit of DNA-dependent RNA polymerase. Binding of $\sigma$ subunit to core enzyme leads the enzyme to specific binding sites on the DNA to start transcription.
• $\rho$ is a transcription terminator that binds a CA-rich sequence called a rut (rho utilization) element on mRNA and migrates in the 5' --> 3' direction until it reaches the transcription complex that is paused at a termination site.
• Hence, it causes the release of the RNA transcript.
• It has an ATP-dependent RNA-DNA helicase activity which promotes translocation of the protein along with the RNA with simultaneous hydrolysis of ATP.

So, the correct answer is option D.