Gene regulation

Question 1

What mechanisms control gene transcription at the level of chromatin?

Answer 1

-DNA methylation
-Histone modifications (acetylation/methylation)

Question 2

what mechanism is responsible for controling transcription at the level of the gene?

Answer 2

DNA methylation

Question 3

What are transcription factors

Answer 3

-They are proteins that interact with the DNA to alter chromatin structure and gene expression
-They bind to various parts of the DNA to help recruit chromatin modifiers and other transcription factors.

Question 4

How do transcription factors work?

Answer 4

-Pioneer TF first bind to iniate opening of chromatin ( convert chromatin to beads on a string)
-This allows additional TF to bind and recruit additiona chromatin remodelling complexes (fully open chromatin)
-Then gene specific TF bind to allow for gene expression (recruitment of GTC and RNA pol II)

Question 5

What are the domains of transcription factors?

Answer 5

-Binding domain ( Helix-turn-Helix)
-Transactivation domain ( glutamine rich domain)

Question 6

What are the main components of the binding domain?

Answer 6

-Two alpha helixes connected by a turn( looks like two tubes connected by a string)
-TF have different families that are based on their binding domains
-Recognition helix is part of the TF that makes contact with DNA in major groove.
-Positioning helix: allows the recognition helix to be in correct position to align with DNA.

Question 7

What is the transactivation domain?

Answer 7

-It is the part of the TF thay is responsible for activating the gene after the binding domain binds to the DNA

Question 8

How does the activation domain activate transcription?

Answer 8

-Attracting and interacting with the general transcription complex to increase the rate of assembly of the complex
-Recruiting chromatin modifiers that open up the chromatin by: Removing histones, allowing RNA pol to read, Reassociating histones with DNA