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Chapter 11. Transposition and Site-Specific Recombination. 29 September and 1 October, 2004. Overview. Conservative Site-Specific Recombination (CSSR) may involve insertion, deletion, or inversion of DNA sequences.

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Chapter 11

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Chapter 11

Transposition and Site-Specific Recombination

29 September and 1 October, 2004


  • Conservative Site-Specific Recombination (CSSR) may involve insertion, deletion, or inversion of DNA sequences.

  • Site-specific recombinases have a mechanism that includes a DNA-protein covalent intermediate.

  • CSSR may be regulated by the presence or absence of accessory proteins.

  • Resolvases are CSSR recombinases that disentangle circular chromosomes.

  • Transposons move using recombination pathways.

  • Transposons may be autonomous or nonautonomous.

  • DNA transposons and viral-like retrotransposons move via a cut/paste mechanism.

  • Retrotransposon movement involves reverse transcription.

  • Some transposons regulate copy number or control target site selection through the use of proteins or antisense RNA.

  • V(D)J recombination uses regulated, specific recombination to generate immune diversity.

Recombination and Transposition

CSSR: Prophage Insertion

Three Classes of CSSR

Recombinase Recognition Sites

Recombinase Mechanism

Serine Recombinases

Tyrosine Recombinases

Mechanism of Cre Recombinase

Cre-DNA Structure

Lambda integration requires architectural proteins.

lInt and IHF stabilize bent DNA.

Hin Inversion

Hin inversion requires Fis bound at an enhancer.

Resolvases disentangle circular DNAs after replication.

FtsK Regulation of the Xer Resolvase Mechanism

FtsK is present at the division closure site.

Conservative and Replicative Transposition

Transposons in Several Genomes

Types of Transposons

Cut and Paste Transposition

Three Mechanisms for Cleaving the Nontransferred Strand

Replicative Transposition

Retrotransposon Movement

Retrotransposon Movement

Retrotransposon Movement

DNA Transposases and retroviral integrases are members of the same protein superfamily.

LINE poly-A Retrotransposon Movement

Tn10 achieves antisense copy control by overlapping promoters.

Antisense Copy Control

Tn10 transposase promoter is active only when hemimethylated.

MuA and MuB participate in selecting Mu transposition target sequences.

MuA disrupts MuB assembly, conferring transposition target immunity.

Clustered Integration of Yeast Ty Elements


V(D)J Recombination

Recombination Signal Sequences

V(D)J Recombination Mechanism


LINES and SINES Again?

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