Chromatin

1. The First Hundred Years.- 2. Development of the Nucleosome Model for Chromatin Structure.- 3. The Structures of DNA.- Composition and Modification of Eukaryotic DNA.- Conformations of DNA in the Solid State.- Hydration of DNA.- DNA Molecules in Solution.- Bent or Curved DNA.- Transformations from the B Form to Other DNA Conformations in Solution.- Topology of DNA: Supercoils and Cruciforms.- 4. The Proteins of Chromatin. I. Histones.- Occurrence and Distribution.- Isolation and Separation of Histones.- The Primary Structures of Histones.- Histone Variants.- Histone Modifications.- Secondary and Tertiary Structure of Histones.- Histone-Histone Interactions.- Noneukaryotic Histone-Like Proteins and the Evolution of the Histones.- 5. The Proteins of Chromatin. II. Nonhistone Chromosomal Proteins.- Enzymes Associated with Chromatin.- Transcription-Regulating Proteins.- Hormone Receptors.- The High Mobility Group (HMG) Proteins.- Chromosomal Structural Proteins.- 6. The Nucleosome.- The Core Particle.- Organization of the Nucleosome Above the Core Particle Level.- Conformational Transitions of the Nucleosome.- 7. Higher-Order Structure.- Nucleosome Arrangement.- Higher-Order Structures: Chromatin Fibers.- Higher-Order Folding of the Chromatin Fiber: The Chromosome.- 8. Chromatin Structure and Transcription.- The Nature of the Problem.- Experimental Approaches.- Chromatin Fractionation.- The Chromatin Structure of Some Specific Genes.- A Role of DNA Methylation?.- Chromosomal Proteins and Gene Activity.- DNA Torsion and Transcription.- A Tentative Model for Gene Activation.- 9. Replication of Chromatin.- DNA Replication.- Histone Synthesis.- Nucleosome Assembly and Histone Distribution.- Nucleosome Segregation.- Nascent Chromatin and Its Maturation.- References.