Outline

Introduction (Figure 25.1)

DNA Methylation (Figure 25.3)

Restriction and Modification

Biology of Restriction and Modification (Figure 25.5, Figure 25.6)

Properties of Restriction and Modification Enzymes (Table 25.1)

Type I

Type II (Table 25.2, Figure 25.7)

Type III

DNA Repair

Types and Consequences of DNA Damage

Biologically Significant DNA Photoproducts: Pyrimidine Dimers (Figure 25.9)

Direct Repair of Damaged DNA Bases: Photoreactivation and Alkyltransferases

Photoreactivation (Figure 25.10)

O⁶-Alkylguanine Alkyltransferase (Figure 25.11)

Nucleotide Excision Repair: Excinucleases (Figure 25.12, Figure 25.13)

Base Excision Repair: DNA-N-Glycosylases (Figure 25.14)

Postreplication Repair: Recombinational Repair and the SOS Response (Item #1, p. 919)

Recombinational Repair (Figure 25.15)

Error-Prone Repair and the SOS Response

Mismatch Repair (Figure 25.16)

Recombination

Classification of the Recombination Processes (Figure 25.17, Table 25.3)

Homologous Recombination

Breaking and Joining of Chromosomes (Figure 25.18, Figure 4.14, Figure 25.19)

Models for Recombination (Figure 25.20, Figure 25.22)

Proteins Involved in Homologous Recombination (Figure 25.23, Figure 25.24, Figure 25.28, Figure 25.29, Figure 25.30)

Site-Specific Recombination (Figure 25.31)

Gene Rearrangements

Immunoglobulin Synthesis: Generating Antibody Diversity (Figure 25.32, Figure 25.33)

Transposable Genetic Elements (Figure 25.34, Figure 25.35, Table 25.4, Figure 25.36, Figure 25.37)

Retroviruses (Figure 25.38, Figure 25.35, Figure 25.39)

Gene Amplification (Figure 25.41)