1. Regulation of transcription in prokaryotes

2. Control of development of phage SPO1 by changing sigma factors
Figure 13-11 2

3. Transcription factors regulate rates of transcription
Figure 13-1 3

4. Activation of transcription by allostery
Figure 13-2 4

5. Cooperative binding of transcription factors
Figure 13-3 5

6. Cooperative effect of binding of transcription factors
Figure 13-5 6

7. Examples: the E. coli lac operon
Box
Structure of the E. coli lac operon 7

8. Transcription of the lac operon is affected by lactose and glucose
Table 13-1 8

9. Figure 14.7b Genomes 3 (© Garland Science 2007)

10. Diauxie
Figure 14.7a Genomes 3 (© Garland Science 2007)

11. Catabolite repression
CAP = catabolite activator protein
Transport of glucose dephosphorylates protein IIAGlc.
Protein IIAGlc also inhibits lactose permease.
Figure 14.7c Genomes 3 (© Garland Science 2007)

12. Lac operon sequences covered by RNA polymerase and transcription factors
Figure 13-4 12

13. Contact between RNA polymerase and the catabolite activator protein (CAP)
Figure 13-6
CAP recruits RNA polymerase to the lac promoter 13

14. Carboxy terminal domain Non- template domain
Figure 13-7 14

15. CAP binds to DNA as a homodimer via a helix-turn-helix DNA-binding motif
CTD of RNA polymerase
CAP
DNA
Figure 13-3 15

16. cAMP induces conformational changes in CAP
Figure 13-8
CAP only binds to DNA in the presence of cAMP
Note: CAP affects expression of more than 100 genes in E. coli 16

17. The Lac repressor binds as a tetramer
Figure 13-9 17

18. Reagents used in transcription from the lac promoter
Figure 13-10
©2006 AAAS 18

19. Transcription factors regulate rates of transcription
Figure 13-1 19

20. Activation of transcription by allostery
Figure 13-2 20

21. Allosteric control of transcription
Examples: transcription factors NtrC and MerR
Figure 13-11
NtrC induces a conformational change in the RNA polymerase by interacting with sigma 54 21

22. Simultaneous binding of RNA polymerase and MerR
Figure 13-11
MerR induces a conformational change in the DNA promoter region when bound to mercury 22

23. The araBAD operon is regulated by cooperative binding of transcription factor AraC
CAP binding site
Figure 13-11
Depending on the presence of arabinose, AraC binds to different sites on the DNA 23

24. Example: Regulation of the lytic and lysogenic infection cycle of bacteriophage lambda

25. The circularized genome of bacteriophage lambda

26. Region of the lambda genome that controls lytic and lysogenic growth

27. Promoter activities during lytic and lysogenic growth
Strong promoters
Weak promoter

28. Binding sites for CI and Cro
Cro binding site
CI binding sites

29. Binding of CI and Cro regulate growth of lambda
Cooperative binding

30. Repressor establishment upon infection is mediated by activator CII

31. The level of activator CII controls transcription of repressor CI and of the integrase gene
Poor growth conditions and high lambda concentration lead to elevated concentrations of CII

32. Antiterminator proteins N and Q control transcription of early genes

33. Antiterminator proteins N and Q control transcription of early genes
N binds to the RNA transcribed from BoxA/B
Binding site of Q protein

34. Transcripts from PI and PL have different 3’ ends that confer different mRNA stability

35. Transcripts from PI and PL have different 3’ ends that confer different stabilities to mRNA