Lecture 9: Control of Gene Expression 1 - Transcriptional Controls

Question 1

True or False:

Each cell has the same genome. Differentiation in cells depends on changes in gene expression.

Answer 1

True

Question 2

What makes cells different?

Answer 2

• Different cells contain the same genes, but they express different sets of proteins.
• Each cell has same genome - differentiation in cells depends on changes in gene expression.

Question 3

What does gene regulation require?

Answer 3

• short stretches of DNA of defined sequence - recognition sites for DNA binding proteins
• gene regulatory proteins - transcription factors that will bind and activate the gene

Question 4

Give an example of a recognition sequence for transcriptional regulatory proteins.

Answer 4

GATA1 -> TGATAG

Question 5

Are the recognition sequences for regulatory proteins proximal or distal to the first exon?

Answer 5

Both - can be proximal or distal to first exon.

Question 6

How many interactions are typically involved in a typical gene regulatory protein-DNA interaction?

Answer 6

10-20 interactions

Question 7

True or False:

Regulatory proteins recognize and bind to bases in the major groove of the DNA.

Answer 7

True

• major groove presents a specific face for each of the specific base pairs
• gene regulatory protein recognizes a specific DNA sequence
• the surface of the protein is extensively complementary to the surface of the DNA region to which it binds
  
  • a series of contacts is made with the DNA involving 4 possible configurations

Question 8

What are the characteristics of a modular sequence specific transcription factor?

Answer 8

• Not every transcription factor will have all modules.
• A transcription factor will have a DNA binding module.
• It could have a dimerization module (form dimer with other protein subunits).
• It will have an activation module (turn on gene).
• Could have a regulatory module (regulate transcription factor).