TRANSCRIPTION

Describe initiation.

TRANSCRIPTION

• RNA polymerase

– Prokaryotes

– Eukaryotes (pol I-III)

• Transcription unit

• Direction of elongation

Stages: Initiation

Stages: Elongation

Stages: Elongation

What are the 2 events that occur simultaneously in this picture?

In what organism can this happen? Prokaryote or eukaryote?

Stages: Termination

Prokaryotes:

◦ end of

termination

signal

Eukaryotes:

◦ past the

signal

AAUAAA

Which is a prokaryotic cell? Eukaryotic cell?

Spot the differences.

What occurs during RNA processing?

RNA Processing

RNA Splicing

Split genes

Aside from removing introns, what else happens during processing?

Both ends of pre-mRNA are usually

altered

Interior sections cut out

Splicing of remaining parts

*In eukaryotes

5’ end (5’ cap)

3’ end (Poly (A) tail)

Functions:

Protects mRNA from degradation

Ribosome binding

Facilitate export of mRNA from nucleus

• Small nuclear ribonucleoproteins (snRNPs)

– Recognize splice sites

• Spliceosome

– Cuts & pastes at splice sites

What are the 2 components of snRNPs?