A human nuclease specific for G4 DNA.
We have identified a human nuclease that specifically cleaves four-stranded DNA stabilized by G quartets (G4 DNA). This nuclease, GQN1 (G quartet nuclease 1), cuts within the single-stranded region 5' of the barrel formed by stacked G quartets. GQN1 does not cleave duplex or single-stranded DNA, Holliday junctions, or G4 RNA. Cleavage depends on DNA structure and not on flanking sequence. Activity is elevated in but not restricted to B cells, making GQN1 a strong candidate for function in immunoglobulin heavy chain class switch recombination. Identification of a mammalian nuclease that specifically cleaves G4 DNA provides further support for the notion that DNA structures stabilized by G quartets form in vivo and function in regulated recombination and genomic evolution.
Sun
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H
Department of Molecular Biophysics and Biochemistry and Genetics, Yale University School of Medicine, New Haven, CT 06520, USA.
Yabuki
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A
Maizels
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N
D001483:Base Sequence; D002460:Cell Line; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D006147:Guanine; D006801:Humans; D008969:Molecular Sequence Data; D013379:Substrate Specificity
D006147:Guanine; D004247:DNA; D003851:Deoxyribonucleases