Insights into Transposition and Site-Specific Recombination Mechanisms in DNA
This chapter focuses on Conservative Site-Specific Recombination (CSSR), detailing its processes including insertion, deletion, and inversion of DNA. It elaborates the role of site-specific recombinases and accessory proteins, including resolvases that untangle circular chromosomes. The chapter also discusses transposons, both autonomous and non-autonomous, detailing their movement mechanisms and regulatory functions. Additionally, it covers V(D)J recombination, emphasizing its significance in generating immune diversity.
Insights into Transposition and Site-Specific Recombination Mechanisms in DNA
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Presentation Transcript
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 achieves antisense copy control by overlapping promoters.
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.