1. Regulating Eukaryotic Gene Expression

2. Why change gene expression? Different cells need different components Responding to the environment Replacement of damaged/worn-out parts Fig 15.1

3. Two points to keep in mind: 1.Cellular components are constantly turned- over. 2.Gene expression takes time: Typically more than an hour from DNA to protein. Most rapidly 15 minutes. Fig 15.1

4. Gene expression can be controlled at many points between DNA and making the final proteins. Changes in the various steps of gene expression control when and how much of a product are produced. Fig 15.1

5. Fig 16.1 Gene Expression is controlled at all of these steps: DNA packaging Transcription RNA processing and transport RNA degradation Translation Post-translational Fig 15.1

6. Fig 16.1 Gene Expression is controlled at all of these steps: DNA packaging Transcription RNA processing and transport RNA degradation Translation Post-translational Fig 15.1

7. Tightly packaged DNA is unavailable. DNA packaging changes as the need for different genes changes. Fig 10.21

8. Different levels of DNA packaging Fig 10.21

9. Histones can be post- translationally modified, which affects their abililty to bind DNA.

10. Acetylation (-COCH 3 ) : post-translational modifications of the histones loosen DNA binding Fig 12.15

11. Acetylation of histones (-COCH 3 ) causes a loosening of the DNA/histone bond…unpackaging the DNA.

12. Fig 15.13 DNA methylation

13. Fig 15.14 DNA methylation often inhibits transcription

14. Fig 15.15 Epigenetics: the inheritance of DNA modifications, including methylaton

25. Fig 16.1 Gene Expression is controlled at all of these steps: DNA packaging Transcription RNA processing and transport RNA degradation Translation Post-translational Fig 15.1

26. Eukaryotic transcription must be activated by binding of transcription factors Fig 12.14

27. Mutations in the promoter show critical nucleotides

28. Enhancers are regulatory regions located some distance away from the promoter Fig 15.12

29. Proteins that help bend DNA can play an important role in transcription Fig 15.12

30. DNA bends to bring different areas in to close contact. Fig 15.12

31. How do eukaryotic cells jointly express several proteins (without operons)?

32. Promoter sequences where transcription factors can bind activating multiple gene in response to the environment

33. Promoters typically have several regulatory sequences Fig 12.13

34. Steroid response element

35. Steroids bind to receptors/transcription factors inside cell get translocated to the nucleus bind to promoters and activate transcription. cytoplasm Fig 15.6

36. Fig 16.1 Gene Expression is controlled at all of these steps: DNA packaging Transcription RNA processing and transport RNA degradation Translation Post-translational Fig 15.1