Chapter 11 Transposition and Site-Specific Recombination 27 and 29 September, 2006
Overview • 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.
DNA Transposases and retroviral integrases are members of the same protein superfamily.
Tn10 transposase promoter is active only when hemimethylated.