1 Introduction.- References.- 2 The structure of the nucleic acids.- 2.1 Monomeric components.- 2.1.1 Pyrimidine bases.- 2.1.2 Purine bases.- 2.1.3 Pentose and deoxypentose sugars.- 2.1.4 Nucleosides.- 2.1.5 Nucleotides.- 2.2 The primary structure of the nucleic acids.- 2.3 Shorthand notation.- 2.4 Base composition analysis of DNA.- 2.5 Molecular weight of DNA.- 2.6 The secondary structure of DNA.- 2.6.1 The basic structures.- 2.6.2 Variations on the B-form of DNA.- 2.6.3 Z-DNA.- 2.6.4 The dynamic structure of DNA.- 2.7 Denaturation and renaturation.- 2.7.1 DNA denaturation: the helix-coil transition.- 2.7.2 The renaturation of DNA: C0t value analysis.- 2.7.3 The buoyant density of DNA.- 2.8 Supercoils, cruciforms and triple-stranded structures.- 2.9 The secondary and tertiary structure of RNA.- 2.10 Chemical reactions of bases, nucleotides and polynucleotides.- 2.10.1 Reactions of ribose and deoxyribose.- 2.10.2 Reactions of the bases.- 2.10.3 Phosphodiester bond cleavage.- 2.10.4 Photochemistry.- References.- 3 Chromosome organization.- 3.1 Introduction.- 3.2 Eukaryote DNA.- 3.2.1 The eukaryote cell cycle.- 3.2.2 Eukaryote chromosomes.- 3.2.3 The allocation of specific genes to specific chromosomes.- 3.2.4 Haploid DNA content (C value).- 3.2.5 Gene frequency.- 3.2.6 Eukaryote gene structure.- 3.3 Chromatin structure.- 3.3.1 Histones and non-histone proteins.- 3.3.2 The nucleosome.- 3.3.3 Nucleosome phasing.- 3.3.4 Higher orders of chromatin structure.- 3.3.5 Loops, matrix and the chromosome scaffold.- 3.3.6 Lampbrush chromosomes.- 3.3.7 Polytene chromosomes.- 3.4 Extranuclear DNA.- 3.4.1 Mitochondrial DNA.- 3.4.2 Chloroplast DNA.- 3.4.3 Kinetoplast DNA.- 3.5 Bacteria.- 3.5.1 The bacterial chromosome.- 3.5.2 The bacterial division cycle.- 3.5.3 Bacterial transformation.- 3.6 Viruses.- 3.6.1 Structure.- 3.6.2 Virus classification.- 3.6.3 Life cycle.- 3.6.4 The Hershey-Chase experiment.- 3.6.5 Virus mutants.- 3.6.6 Virus nucleic acids.- 3.6.7 The information content of viral nucleic acids.- 3.6.8 Lysogeny and transduction.- 3.6.9 Tumour viruses and animal cell transformation.- 3.6.10 Viroids.- 3.6.11 Prions.- 3.7 Plasmids and transposons 77.- References.- 4 Degradation and modification of nucleic acids.- 4.1 Introduction and classification of nucleases.- 4.2 Non-specific nucleases.- 4.2.1 Non-specific endonucleases.- 4.2.2 Non-specific exonucleases.- 4.3 Ribonucleases (RNases).- 4.3.1 Endonucleases which form 3?-phosphate groups.- 4.3.2 Endonucleases which form 5?-phosphate groups.- 4.3.3 RNA exonucleases.- 4.3.4 Ribonucleases which act on RNA:DNA hybrids (RNase H).- 4.3.5 Double-stranded RNA-specific ribonucleases.- 4.3.6 Ribonuclease inhibitors.- 4.4 Polynucleotide phosphorylase (PNPase).- 4.5 Deoxy ribonucleases (DNases).- 4.5.1 Endonucleases.- 4.5.2 Exonucleases.- 4.5.3 Restriction endonucleases.- 4.6 Nucleic acid methylation.- 4.6.1 DNA methylation.- 4.6.2 RNA methylation and other RNA nucleotide modifications.- 4.7 Nucleic acid kinases and phosphatases.- 4.7.1 Bacteriophage polynucleotide kinase.- 4.7.2 Eukaryotic DNA and RNA kinases.- 4.8 Base exchange in RNA and DNA.- References.- 5 The metabolism of nucleotides.- 5.1 Anabolic pathways.- 5.2 The biosynthesis of the purines.- 5.3 Preformed purines as precursors.- 5.4 The biosynthesis of the pyrimidines.- 5.5 The biosynthesis of deoxyribonucleotides and its control.- 5.6 The biosynthesis of thymine derivatives.- 5.7 Aminopterin in selective media.- 5.8 Formation of nucleoside triphosphates.- 5.9 General aspects of catabolism.- 5.10 Purine catabolism.- 5.11 Pyrimidinecatabolism.- References.- 6 Replication of DNA.- 6.1 Introduction.- 6.2 Semiconservative replication.- 6.3 The replication fork.- 6.3.1 Discontinuous synthesis.- 6.3.2 Okazaki pieces.- 6.3.3 Direction of chain growth.- 6.3.4 Initiation of Okazaki pieces.- 6.3.5 Continuous synthesis.- 6.4 Enzymes of DNA synthesis.- 6.4.1 Introduction.- 6.4.2 DNA polymerases.- 6.4.3 DNA ligases.- 6.4.4 Helix-destabilizing proteins (HD) or single-stranded DNA- binding proteins (ssb).- 6.4.5 DNA unwinding proteins or DNA helicases (DNA-dependent ATPases).- 6.4.6 Topoisomerases.- 6.5 Fidelity of replication.- 6.6 In vitro systems for studying DNA replication.- 6.6.1 dna mutants.- 6.6.2 Permeable cells.- 6.6.3 Cell lysates.- 6.6.4 Soluble extracts.- 6.6.5 Reconstruction experiments.- 6.7 Molecular biology of the replication fork.- 6.7.1 Lagging-strand synthesis.- 6.7.2 Leading-strand synthesis.- 6.7.3 RF replication.- 6.8 Initiation of replication-general.- 6.8.1 Methods of locating the origin and direction of replication.- 6.8.2 Replicons.- 6.8.3 Rate of replication.- 6.8.4 Origin strategies.- 6.8.5 Positive or negative control of initiation.- 6.9 Initiation of replication-specific examples.- 6.9.1 Small single-stranded phage.- 6.9.2 Double-stranded phage.- 6.9.3 Plasmids.- 6.9.4 Bacteria.- 6.9.5 Mitochondria.- 6.9.6 Double-stranded cyclic DNA viruses (SV40 and polyoma).- 6.9.7 Adenoviruses.- 6.9.8 Yeast.- 6.9.9 Higher eukaryotes.- 6.9.10 Retroviruses.- 6.10 Termination of replication.- 6.10.1 Cyclic chromosomes.- 6.10.2 Small linear chromosomes.- 6.10.3 Telomeres.- 6.11 Replication complexes.- 6.12 Chromatin replication.- References.- 7 Repair, recombination and DNA rearrangement.- 7.1 Introduction.- 7.2 Mutations and mutagens.- 7.2.1 Base and nucleoside analogues.- 7.2.2 Alkylating agents.- 7.2.3 Intercalating agents.- 7.2.4 The effects of ionizing radiation.- 7.2.5 Ultraviolet radiation.- 7.3 Repair mechanisms.- 7.3.1 Reversal of damage.- 7.3.2 Excision repair.- 7.3.3 Mismatch repair.- 7.3.4 Post-replication repair.- 7.4 Recombination.- 7.4.1 E. coli rec system and single-strand invasion.- 7.4.2 Reciprocal recombination between duplex DNA molecules.- 7.4.3 Site-specific recombination.- 7.5 Gene amplification.- 7.5.1 Developmental amplification.- 7.5.2 Amplification by chemical selection.- 7.5.3 Mechanism of amplification.- 7.6 Gene duplication and pseudogenes.- 7.6.1 Multiple related copies of eukaryotic genes.- 7.6.2 Mechanism of tandem gene duplication.- 7.6.3 Pseudogenes.- 7.6.4 Concerted evolution of duplicated genes.- 7.7 Transposition of DNA.- 7.7.1 Transposable elements.- 7.7.2 Transposition in prokaryotes.- 7.7.3 Transposition in eukaryotes.- 7.8 Gene conversion.- 7.8.1 Yeast mating-type locus.- 7.8.2 Variant surface glycoprotein (VSG) genes in trypanosomes.- 7.9 Gene rearrangements.- 7.9.1 Immunoglobulin genes.- 7.9.2 T-cell receptor genes.- 7.9.3 Other gene rearrangements.- 7.10 Chromosomal translocations.- References.- 8 RNA biosynthesis.- 8.1 DNA-dependent RNA polymerases.- 8.1.1 Bacterial DNA-dependent RNA polymerase.- 8.1.2 Eukaryotic DNA-dependent RNA polymerases.- 8.2 Prokaryotic RNA synthesis.- 8.2.1 Prokaryotic initiation of transcription.- 8.2.2 Elongation of RNA transcripts.- 8.2.3 Termination of transcription in prokaryotes.- 8.3 Eukaryotic RNA synthesis.- 8.3.1 Initiation by RNA polymerase II.- 8.3.2 Initiation by RNA polymerase III.- 8.3.3 Initiation by RNA polymerase I.- 8.3.4 Eukaryotic termination.- 8.3.5 Transcription of mitochondrial and chloroplast genes.- 8.4 RNA polymerases and RNA synthesis in DNA viruses.- 8.5 The replication of RNA viruses by RNA-dependent RNA polymerase (Replicase).- 8.5.1 RNA bacteriophage.- 8.5.2 Eukaryotic RNA viruses.- References.- 9 The arrangement of genes, their transcription and processing.- 9.1 Transcription and processing of prokaryotic and bacteriophage mRNA.- 9.2 The organization of eukaryotic protein-encoding genes.- 9.2.1 Genes are often discontinuous.- 9.2.2 Gene families and gene clustering.- 9.3 Transcription and processing of eukaryotic pre-messenger RNA.- 9.3.1 The nature of gene transcripts.- 9.3.2 Caps and 5?-leader sequences of eukaryotic mRNA.- 9.3.3 Poly adenylate tails, 3? -processing and 3? -non-coding sequences of eukaryotic mRNAs.- 9.3.4 Removal of intron transcripts from pre-mRNA.- 9.4 The arrangement of rRNA genes, their transcription and processing.- 9.4.1 The prokaryotic rRNA genes and their processing.- 9.4.2 The rRNA genes of eukaryotes.- 9.4.3 The transcription and processing of eukaryotic ribosomal RNA.- 9.5 The arrangement and expression of tRNA genes.- 9.5.1 tRNA genes.- 9.5.2 The processing of tRNA.- 9.6 The arrangement and expression of mitochondrial and chloroplast genes.- 9.6.1 Protein-encoding genes of mitochondria and chloroplasts.- 9.6.2 Mitochondrial and chloroplast rDNA.- 9.6.3 Mitochondrial and chloroplast tRNA genes.- 9.6.4 The introns of mitochondrial genes and their splicing.- 9.7 A postscript on splicing.- References.- 10 Control of transcription and mRNA processing.- 10.1 The regulation of prokaryotic RNA chain initiation.- 10.1.1 Induction of the lac operon - a negative control system.- 10.1.2 Repression of the trp operon.- 10.1.3 Catabolite repression - a positive control system.- 10.1.4 Other variations in the control of initiation at bacterial operons.- 10.1.5 The repressors of bacteriophage lambda(phage ?).- 10.1.6 The interaction of repressor and activator proteins with DNA.- 10.2 The regulation of the termination of transcription in prokaryotes.- 10.2.1 Attenuation.- 10.2.2 Antiterminators of transcription.- 10.3 Modification of prokaryotic RNA polymerase.- 10.3.1 Diversity in sigma factor.- 10.3.2 Bacteriophage T4 modulation of host RNA polymerase.- 10.4 Control of gene expression in eukaryotes.- 10.4.1 Promotors.- 10.4.2 Cis-acting control elements.- 10.4.3 Trans-acting factors.- 10.4.4 The nature of active chromatin.- 10.4.5 Multiple gene copies, amplification and gene rearrangement.- 10.5 Regulation of gene expression by RNA.- 10.5.1 Antisense RNA.- 10.5.2 Identifiers.- 10.6 The control of pre-mRNA processing.- 10.6.1 3?-Processing and poly-adenylation.- 10.6.2 Splicing of pre-mRNA.- 10.6.3 Control of the rate of processing and nuclear transport of mRNA.- References.- 11 The translation of mRNA: protein synthesis.- 11.1 The structure of tRNA.- 11.2 The genetic code.- 11.2.1 The codon as a nucleotide triplet.- 11.2.2 Assignment of amino acid codons.- 11.2.3 Assignment of termination codons.- 11.2.4 Assignment of initiation codons.- 11.2.5 The degeneracy of the genetic code.- 11.2.6 Variations in the code and codon usage.- 11.3 Aminoacylation of tRNA.- 11.4 General aspects of polypeptide formation.- 11.5 The events on the bacterial ribosome.- 11.5.1 Chain initiation.- 11.5.2 Chain elongation.- 11.5.3 Chain termination.- 11.6 The events on the eukaryotic ribosome.- 11.6.1 Chain initiation.- 11.6.2 Chain elongation.- 11.6.3 Chain termination.- 11.7 The control of the cellular location of the products of translation.- 11.7.1 Secreted proteins.- 11.7.2 Membrane proteins.- 11.7.3 Organelle proteins.- 11.8 The ribosome.- 11.8.1 Structure of the components.-11.8.2 Organization of components in the ribosome.- 11.8.3 Functional domains in the ribosome.- 11.9 Other protein-synthesizing systems.- 11.9.1 Archaebacteria.- 11.9.2 Mitochondria.- 11.9.3 Chloroplasts.- 11.10 The regulation of translation in prokaryotes.- 11.10.1 Control of the translation of bacteriophage mRNA.- 11.10.2 Autogenous control of ribosomal protein synthesis.- 11.10.3 Codon usage and translational control.- 11.11 The regulation of translation in eukaryotes.- 11.11.1 The role of mRNA structure.- 11.11.2 The role of protein phosphorylation.- 11.11.3 Regulation in cells infected with viruses.- 11.11.4 Translationally inactive mRNA.- 11.12 The coupling of transcription and translation.- 11.13 Translational accuracy and misreading.- 11.13.1 Ribosomal optimization of translational accuracy.- 11.13.2 Suppression.- References.- Appendix: methods of studying nucleic acids.- A. 1 Occurrence and chemical analysis.- A. 1.1 Chemical determination of nucleic acids in tissues 459.- A. 1.2 Analysis of base composition and nearest-neighbour frequency.- A. 1.3 Estimation of the molecular weight of DNA.- A.2 Isolation and separation of nucleic acids.- A.2.1 Isolation and separation of DNA.- A.2.2 Isolation and separation of RNA.- A. 3 Hybridization of nucleic acids.- A.4 Methods of labelling nucleic acids.- A. 4.1 General labelling methods.- A.4.2 End-labelling methods.- A.5 Determination of nucleic acid sequences.- A. 5.1 Determination of DNA sequences.- A.5.2 Determination of RNA sequences.- A.6 Restriction mapping of DNA.- A.7 Cloning DNA.- A.7.1 The principles 480.- A.7.2 The construction of recombinants and their introduction into bacteria.- A.7.3 The identification of recombinant DNA clones.- A. 8 Analysis and manipulation of cloned DNA.- A. 8.1 Mapping of RNA transcripts 491.- A.8.2 Identification of regions of DNA that interact with proteins.- A.8.3 Allocation of cloned genes to specific chromosomes.- A.8.4 Expression in eukaryotic cells.- A.9 Chemical synthesis of oligonucleotides.- A.10 Cell-free systems for transcription ana translation.- A.11 The use of inhibitors in the study of gene expression.- References.