Organisation of Pro and Eu genome tutorial Q5 essay [8 marks]

1. Are non-coding DNA sequences that are bound by transcription factors

2. involved in regulating gene expression

3. 3 types of control elements include: promoter, enhancers and silencers.   

4. Promoter serves as recognition site for transcription factors and RNA polymerase

5. [more details ..] -  TATA box within promoter (consisting of 5’-TATAAA-3’) is recognized and bound by general transcription factors to recruit RNA polymerase to the promoter region

6. [relate back to how transcription is influenced] -  binding only produces basal / low levels of transcription 

7. Enhancers are distal control elements bound by activators.

8. a looping mechanism brings the bound activator to interact with the RNA polymerase  and transcription factors at the TATA site

9. [relate back to how transcription is influenced] -  Interaction of activators with RNA polymerase and/or general transcription factors increases the transcription of a gene.                                           

10. Silencers are distal control elements bound by repressors, 

11. [relate back to how transcription is influenced] -  Interaction inhibit transcription / gene expression

11. [Extra: some examples by which repressors work] - 

·          binding of repressor to DNA control elements mask the binding site of activators; OR

·         Binding of repressor to silencer and a certain transcription factor prevents further assembly of general transcription factors

Click to enlarge

(Diagram --> Ignore the coactivators)