Rec A-independent homologous recombination induced by a putative fold-back tetraplex DNA.
We have recently reported that a GC-rich palindromic repeat sequence presumably adopts a stable fold-back tetraplex DNA structure under supercoiling. To establish the biological significance of this structure, we inserted this sequence between two direct repeat sequences, separated by 200 bp, in a plasmid. We then investigated the effect of this sequence on homologous recombination events. Here we report that the putative fold-back DNA tetraplex structure induces homologous recombination between direct repeat sequences. Interestingly, this recombination event is independent of recA, a major driving force for homologous recombination. We think that the fold-back structure forces the repeat sequences to come into close proximity and therefore leads to strand exchange. Although triplex-induced recombination has been well documented, our results for the first time directly establish the potential of a tetraplex structure to induce recA-independent homologous recombination in vivo. This finding might have a significant implication for site-directed gene deletion in the context of the correction of genetic defects.
Centre for Biotechnology, Jawaharlal Nehru University, New Mehrauli Road, New Delhi 110067, India. arun.shukla@mpibp-frankfurt.mpg.de
Arun Kumar
AK
Shukla
Kunal B
KB
Roy
D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D004260:DNA Repair / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D054856:G-Quadruplexes; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics*; D011995:Recombination, Genetic / Q000187:drug effects*; D012091:Repetitive Sequences, Nucleic Acid; D017384:Sequence Deletion
D004269:DNA, Bacterial; D004247:DNA; D011938:Rec A Recombinases