What causes the termination of transcription?

Transcription termination occurs in a reaction coupled to RNA 3′-end processing. Most eukaryotic mRNA precursors are cleaved in a site-specific manner in the 3′-untranslated region, followed by polyadenylation of the upstream cleavage product. A large number of proteins is involved in these reactions.

What causes termination of transcription in eukaryotes?

RNA Polymerase II terminates transcription at random locations past the end of the gene being transcribed. The newly-synthesized RNA is cleaved at a sequence-specified location and released before transcription terminates.

How does RNA polymerase III terminate transcription?

By being sequence-specific, precise and efficient, transcription termination by pol III not only defines the 3′ end of the nascent RNA which directs subsequent association with the stabilizing La protein, it also prevents transcription into downstream DNA and promotes efficient recycling.

What is the transcription termination sequence?

termination sequence. The sequence of DNA which signals the transcription to stop. in the gene (Fig. 11). The termination sequences signal the end of the gene and can work in a number of ways.

How does eukaryotic transcription is terminated?

The termination of transcription is different for the different polymerases. Unlike in prokaryotes, elongation by RNA polymerase II in eukaryotes takes place 1,000–2,000 nucleotides beyond the end of the gene being transcribed. This pre-mRNA tail is subsequently removed by cleavage during mRNA processing.

What does RNA polymerase III do?

RNA polymerase III (Pol III) transcribes various small stable RNAs that are essential in multiple cellular pathways, including pre-mRNA splicing (U6 snRNA) and protein synthesis (5S rRNA, tRNAs)2.

What is termination site?

Termination in bacteria Rho-dependent termination. The terminator is a region of DNA that includes the sequence that codes for the Rho binding site in the mRNA, as well as the actual transcription stop point (which is a sequence that causes the RNA polymerase to pause so that Rho can catch up to it).

How is transcription terminated in eukaryotes?

Transcription termination occurs in a reaction coupled to RNA 3′-end processing. Most eukaryotic mRNA precursors are cleaved in a site-specific manner in the 3′-untranslated region followed by polyadenylation of the upstream cleavage product.

Is the termination of transcription independent of 3′ processing?

Evidence suggests that the termination of transcription and 3′ processing are indeed not independent but coupled. For efficient 3′ end processing, two separate sequence elements are required: the AATAAA sequence and a second GT-rich element immediately downstream of the cleavage site at which poly (A) is added.

What is the role of Rho factor in transcription termination?

Rho factor mediates termination of transcription by first binding to a site on the nascent transcript, then using its ATP hydrolysis activity as a source of energy to dissociate the transcript from its ternary complex with RNA polymerase and DNA.

What happens to pre-mRNA after termination of transcription?

Soon after the termination of transcription, most vertebrate hnRNA (pre-mRNA) will be post-transcriptionally processed after exiting the nucleus into a form that can be translated (Figure 1.3 ).