17.1 Introduction 17.2 The mating pathway is triggered by pheromone-receptor interactions 17.3 The mating response activates a G protein 17.4 Yeast can switch silent and active loci for mating type 17.5 The MAT locus codes for regulator proteins 17.6 Silent cassettes at HML and HMR are repressed 17.7 Unidirectional transposition is initiated by the recipient MAT locus 17.8 Regulation of HO expression 17.9 Trypanosomes switch the VSG frequently during infection 17.10 New VSG sequences are generated by gene switching 17.11 VSG genes have an unusual structure 17.12 The bacterial Ti plasmid causes crown gall disease in plants 17.13 T-DNA carries genes required for infection 17.14 Transfer of T-DNA resembles bacterial conjugation 17.15 Selection of amplified genomic sequences 17.16 Transfection introduces exogenous DNA into cells 17.17 Genes can be injected into animal eggs 17.18 ES cells can be incorporated into embryonic mice 17.19 Gene targeting allows genes to be replaced or knocked out

16.1 Introduction 16.2 The retrovirus life cycle involves transposition-like events 16.3 Retroviral genes codes for polyproteins 16.4 Viral DNA is generated by reverse transcription 16.5 Viral DNA integrates into the chromosome 16.6 Retroviruses may transduce cellular sequences 16.7 Yeast Ty elements resemble retroviruses 16.8 Many transposable elements reside in D. melanogaster 16.9 Retroposons fall into two classes 16.10 The Alu family has many widely dispersed members

12.1 Introduction 12.2 Replicons can be linear or circular 12.3 Origins can be mapped by autoradiography and electrophoresis 12.4 The bacterial genome is a single circular replicon 12.5 Each eukaryotic chromosome contains many replicons 12.6 Isolating the origins of yeast replicons 12.7 D loops maintain mitochondrial origins 12.8 The problem of linear replicons

11.1 Introduction 11.2 Lytic development is divided into two periods 11.3 Lytic development is controlled by a cascade 11.4 Functional clustering in phages T7 and T4 11.5 Lambda immediate early and delayed genes are needed for both lysogeny and the lytic cycle

10.1 Introduction 10.2 Regulation can be negative or positive 10.3 Structural gene clusters are coordinately controlled 10.4 The lac genes are controlled by a repressor 10.5 The lac operon can be induced 10.6 Repressor is controlled by a small molecule inducer

9.1 Introduction 9.2 Transcription is catalyzed by RNA polymerase 9.3 The transcription reaction has three stages 9.4 A stalled RNA polymerase can restart 9.5 RNA polymerase consists of multiple subunits 9.6 RNA Polymerase consists of the core enzyme and sigma factor 9.7 Sigma factor is released at initiation 9.8 Sigma factor controls binding to DNA 9.9 Promoter recognition depends on consensus sequences

23.1 Introduction 23.2 Group I introns undertake self-splicing by transesterification 23.3 Group I introns form a characteristic secondary structure 23.4 Ribozymes have various catalytic activities 23.5 Some introns code for proteins that sponsor mobility 23.6 The catalytic activity of RNAase P is due to RNA 23.7 Viroids have catalytic activity 23.8 RNA editing occurs at individual bases

22.1 Introduction 22.2 Nuclear splice junctions are short sequences 22.3 Splice junctions are read in pairs 22.4 Nuclear splicing proceeds through a lariat 22.5 snRNAs are required for splicing 22.6 U1 snRNP initiates splicing 22.7 The E complex can be formed in alternative ways 22.8 5 snRNPs form the spliceosome

21.1 Introduction 21.2 Response elements identify genes under common regulation 21.3 There are many types of DNA-binding domains 21.4 A zinc finger motif is a DNA-binding domain 21.5 Steroid receptors are transcription factors 21.6 Steroid receptors have zinc fingers 21.7 Binding to the response element is activated by ligand-binding 21.8 Steroid receptors recognize response elements by a combinatorial code

20.1 Introduction 20.2 Eukaryotic RNA polymerases consist of many subunits 20.3 Promoter elements are defined by mutations and footprinting 20.4 RNA polymerase I has a bipartite promoter 20.5 RNA polymerase III uses both downstream and upstream promoters 20.6 The startpoint for RNA polymerase II 20.7 TBP is a universal factor 20.8 TBP binds DNA in an unusual way