1. Chapter 5
General Recombination

2. Repair of replication forks
Figure 5-53 (part 1 of 2) Molecular Biology of the Cell (© Garland Science 2008)

3. Repair of replication forks
Figure 5-53 (part 2 of 2) Molecular Biology of the Cell (© Garland Science 2008)

4. General recombination transfers information from one DNA strand to another

5. DNA crossovers create heteroduplex DNA

6. General recombination in meiosis

7. General recombination in meiosis
ds break
synapse
strand invasion
heteroduplex formation
branch migration
resolution

8. Recombination is similar to DNA hybridization

9. Resolution of recombination depends on where breaks occur
Patch
Splice

10. Spo11
RecBCD/MRN
RecA
DNA pol
RuvA-RuvB
RuvC

11. RecBCD Helicase/Nuclease
Processes DS breaks to form ssDNA ends
Loads RecA onto the ssDNA ends
Destroys foreign DNA
Binds ends and tracks along the DNA - ATP hydrolysis

12. The RecBCD complex prepares DNA ends for homologous recombination

13. Chi sites increase the rate of homologous recombination

14. The structure of the RecA/Rad51 filament

15. RecA/Rad51 filaments

16. RecA catalyzes synapse formation

17. How does a broken strand find a homologous donor?
Rapid Exchange of A:T Base Pairs Is Essential for Recognition of DNA Homology by Human Rad51 Recombination Protein
Molecular Cell, Vol. 4, 705–714, November, 1999,
Ravindra C. Gupta,* Ewa Folta-Stogniew,†
Shawn O’Malley,* Masayuki Takahashi,‡
and Charles M. Radding*†§
Rad51
Triplex DNA formed by base “flipping”?

18. RecA contains two DNA binding sites

19. RecA catalyzes branch migration

20. Figure 5-58 Molecular Biology of the Cell (© Garland Science 2008)

21. The Holliday junction

22. A EM micrograph of a Holliday junction

23. Ruv proteins catalyze double branch migration
RuvA: Holiday junction binding protein (tetramer)
RuvB: ATP dependent helicase (hexamer)

24. An alternate representation of RuvAB

25. RuvC resolves Holiday structures

26. RecBCD RecA RuvA-RuvB RuvC MRX complex Mre11, Rad51, Dmc1 BRCA1, BRCA2
Xrs2 (Nbs1)
Rad51, Dmc1
BRCA1, BRCA2
Spo11
DNA pol

27. DS break repair
Figure Molecular Biology of the Cell (© Garland Science 2008)

28. Gene conversion

29. Gene conversion
Figure Molecular Biology of the Cell (© Garland Science 2008)

30. Heteroduplex formation at sites of gene conversion and crossover
Figure Molecular Biology of the Cell (© Garland Science 2008)

31. Gene conversion by mismatch correction
Figure Molecular Biology of the Cell (© Garland Science 2008)

32. Resolution of recombinant intermediates in meiotic and mitotic cells

33. Resolution of recombination depends on where breaks occur
Patch
Splice

34. Mismatch detection prevents recombination of similar sequences
Figure Molecular Biology of the Cell (© Garland Science 2008)

35. Recombination controls yeast mating types

36. Chapter 5
Site-Specific Recombination

37. The human genome contains many transposable elements

38. Table 5-3 Molecular Biology of the Cell (© Garland Science 2008)

39. Bacterial transposable elements

40. Cut-and-paste transposition

41. The structure of a transposase bound to DNA

42. Replicative cut-and-paste transposition

43. Retrovirus lifecycle
Figure Molecular Biology of the Cell (© Garland Science 2008)

44. Structure of reverse transcriptase
Figure 5-72a Molecular Biology of the Cell (© Garland Science 2008)

45. Structure of reverse transcriptase
Figure 5-72b Molecular Biology of the Cell (© Garland Science 2008)

46. Transposition of retroviral like transposable elements

47. Transposition of non-retroviral like transposable elements
Figure 5-74 (part 1 of 2) Molecular Biology of the Cell (© Garland Science 2008)

48. Transposition of non-retroviral like transposable elements
Figure 5-74 (part 2 of 2) Molecular Biology of the Cell (© Garland Science 2008)

49. Expansion of repetitive elements in mouse and human lineages
Figure Molecular Biology of the Cell (© Garland Science 2008)

50. Transposable elements near the -globin gene cluster
Alu - green
L1 - red
Bl - blue
L1 - yellow

51. The human genome contains many transposable elements

52. Table 5-3 Molecular Biology of the Cell (© Garland Science 2008)

53. Conservative site-specific recombination can rearrange DNA

54. Insertion of lambda DNA into a bacterial chromosome

55. Insertion of lambda DNA into a bacterial chromosome
attP
attB
Integration Host Factor (IHF)
attL
attR

56. The lambda phage life cycle

57. Use of site-specific recombination to control gene expression

58. Inactivation of a marker gene by recombination

59. Inactivation of a marker gene by recombination
Figure Molecular Biology of the Cell (© Garland Science 2008)

60. Inactivation of a marker gene by recombination
Figure 5-79a Molecular Biology of the Cell (© Garland Science 2008)

61. Figure 5-79b Molecular Biology of the Cell (© Garland Science 2008)

62. Points to understand:
The differences between site-specific and general recombination
The consequences of each type of recombination
The three types of transposable elements
How the elements move
How the TEs relate to viruses and phage
Conservative site specific recombination and how it is used by cells and experimental biologists