Question

In eukaryotic transcription termination the ____ signal causes the polymerase to fall off of the DNA and transcription ends

Answer 1

In eukaryotic transcription termination the transcription termination signal causes the polymerase to fall off of the DNA and transcription ends.

In eukaryotes transcription is done with help of RNA Polymerase enzymes, which are 3 types.

- RNA POLYMERASE 1st

- RNA POLYMERASE 2nd

- RNA POLYMERASE 3rd.

The termination of transcription is different for the three different eukaryotic RNA polymerases.

The r-RNA transcribed by RNA POLYMERASE 1 contain a specific sequence of basepairs (11 bp long in humans) that is recognized by a termination protein called TTF-1 (Transcription Termination Factor for RNA Polymerase I.) This protein binds the DNA at its recognition sequence and blocks further transcription, causing the RNA Polymerase I to disengage from the template DNA strand and to release its newly-synthesized RNA.

Transcription with help of RNA POLYMERASE 2nd ter mination:- RNA POLYMERASE 2nd 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.

The process of termination in RNA polymerase 3rd involves an mRNA hairpin similar to rho-independent termination of transcription in prokaryotes.