Lecture 12 - Regulation of transcription in eukaryotes

Question 1

What is the mediator?

Answer 1

A large modular complex (21 proteins) that conveys regulatory signals from gene-specific activators and repressors to the core transcriptional machinery.

Question 2

What is an enhancer?

Answer 2

Regulatory sequences that act at a distance (up to several thousand bases away).
They lack promoter activity themselves
Dramatically enhance the activity of promoters
Can be located upstream or downstream of the promoter
Can act in either orientation
Can be composed of multiple sequence elements

Question 3

What is a basal factor?

Answer 3

Required by RNAP II to form the initiation complex at all promoters.

Question 4

What is an activator?

Answer 4

Binds to DNA sequence elements and stimulates transcription

Question 5

What are co-activators?

Answer 5

factors required for transcriptional activation but that do not bind directly to DNA.