11.2 - The activity of positive regulatory transcription factors - Activators

Question 1

What are the 3 main classes of activators?

Answer 1

1. True activator
2. Antirepressors
3. Architectural proteins

Question 2

How is the activity of a true activator regulated?

Answer 2

1. protein synthesis
2. protein modification
3. ligand binding (may influence localization of protein)
4. inhibitors that affect protein binding
5. selecting the right partner for activation binding
6. cleavage of an inactive precursor

Question 3

What is the function of antirepressors?

Answer 3

• recruit histone modification
  enzymes to bound activators
  to convert chromatin from
  closed state to open state
• functions only on chromatin templates

Question 4

What is the function of architectural proteins?

Answer 4

• to bend DNA in order to prevent or allow complex formations
• when regulator binds to bottom/top, proteins contact/do not contact e/o