Excision of the Drosophila mariner transposon Mos1. Comparison with bacterial transposition and V(D)J recombination.
It has been proposed that the modern immune system has evolved from a transposon in an ancient vertebrate. While much is known about the mechanism by which bacterial transposable elements catalyze double-strand breaks at their ends, less is known about how eukaryotic transposable elements carry out these reactions. We have examined the mechanism by which mariner, a eukaryotic transposable element, performs DNA cleavage. We show that the nontransferred strand is cleaved initially, unlike prokaryotic transposons which cleave the transferred strand first. First strand cleavage is not tightly coupled to second strand cleavage and can occur independently of synapsis, as happens in V(D)J recombination but not in transposition of prokaryotic transposons. Unlike V(D)J recombination, however, second strand cleavage of mariner does not occur via a hairpin intermediate.
Dawson
Angela
A
Institute of Cell and Molecular Biology, University of Edinburgh, Kings Buildings, Edinburgh EH9 3JR, United Kingdom. angela.dawson@ed.ac.uk
Finnegan
David J
DJ
D000818:Animals; D001419:Bacteria / Q000235:genetics*; D001483:Base Sequence; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D015321:Gene Rearrangement; D007107:Immune System / Q000502:physiology; D009690:Nucleic Acid Conformation; D011995:Recombination, Genetic; D013997:Time Factors; D019895:Transposases
D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; C111652:mariner transposases; D004247:DNA; D019895:Transposases