Regulation of Gene Expression in Bacteria and Their Viruses CHAPTER 10 Regulation of Gene Expression in Bacteria and Their Viruses Copyright 2008 © W H Freeman and Company
CHAPTER OUTLINE 10.1 Gene regulation 10.2 Discovery of the lac system: negative control 10.3 Catabolite repression of the lac operon: positive control 10.4 Dual positive and negative control: the arabinose operon 10.5 Metabolic pathways and additional levels of regulation: attenuation 10.6 Bacteriophage life cycles: more regulators, complex operons 10.7 Alternative sigma factors regulate large sets of genes
Regulatory proteins control transcription Figure 10-2
Allosteric effectors bind to regulatory proteins Figure 10-3
Repressor protein controls the lac operon Figure 10-4
Lactose is broken down into two sugars Figure 10-5
The lac operon is transcribed only in the presence of lactose Figure 10-6a
The lac operon is transcribed only in the presence of lactose Figure 10-6b
Structure of IPTG Figure 10-7
Table 10-1
Operators are cis-acting Figure 10-8
Table 10-2
Repressors are trans-acting Figure 10-9
Table 10-3
The repressor contains a lactose-binding site Figure 10-10
RNA polymerase contacts the promoter at specific sequences Figure 10-11
The operator is a specific DNA sequence Figure 10-12
Glucose levels control the lac operon Figure 10-13
Glucose levels control the lac operon Figure 10-13a
Glucose levels control the lac operon Figure 10-13b
Many DNA binding sites are symmetrical Figure 10-14
Binding of CAP bends DNA Figure 10-15
CAP and RNA polymerase bind next to each other Figure 10-16
Negative and positive control of the lac operon Figure 10-17
Negative and positive control of the lac operon Figure 10-17a
Negative and positive control of the lac operon Figure 10-17b
Negative and positive control of the lac operon Figure 10-17c
Repression and activation compared Figure 10-18
Repression and activation compared Figure 10-18a
Repression and activation compared Figure 10-18b
Map of the ara operon Figure 10-19
AraC serves as an activator and as a repressor Figure 10-20
Gene order in the trp operon corresponds to reaction order in the biosynthetic pathway Figure 10-21
The trp mRNA leader sequence contains an attenuator region and two tryptophan codons Figure 10-22
Abundant tryptophan attenuates transcription of the trp operon Figure 10-23
Leader peptides of amino acid biosynthesis operons Figure 10-24
The life cycle of bacteriophage Figure 10-25
Phage genome is organized for coordinate control Figure 10-26
The lysogenic-versus-lytic cycle is determined by repressor occupancy on the OR operators Figure 10-27
Helix-turn-helix is a common DNA-binding motif Figure 10-28
Amino acid side chains determine the specificity of DNA binding Figure 10-29
factors control clusters of unlinked genes Figure 10-30a
factors control clusters of unlinked genes Figure 10-30b