Environmental Effects and Epigenetics

Question 1

What are housekeeping genes?

Answer 1

Proteins and enzymes commonly expressed in different cell-types (eg. histone)

Question 2

What is a gene promoter?

Answer 2

5’ regulatory sequence that controls transcription initiation

Question 3

Function of general transcription factors

Answer 3

• Recognise and bind gene promoter
• Recruit RNA polymerase II
• Allow a basal level of transcription

Question 4

What is rate of transcription controlled by?

Answer 4

• Enhancers (DNA sequence up- or downstream)
• Gene-specific transcription factors (regulatory protein)

Question 5

What is the interaction between enhancers and gene-specific transcription factors?

Answer 5

• GSTFs bind enhancers
• Can activate or repress transcription

Question 6

What enzymes are involved in (de)acetylation of histones?

Answer 6

• Histone acetyl transferases = acetylation
• Histone deacetylases = deacetylation

Question 7

How does the environment influence deacetylation?

Answer 7

Environmental factors and therapeutic drugs inhibit histone deacetylases

Question 8

How do humans equalise expression levels between the sexes?

Answer 8

In females, one X chromosome is inactivated early in development