Open AccessT7 endonuclease I resolves Holliday junctions formedin vitroby RecA protein
Author(s) -
Berndt Müller,
Christine Jones,
Stephen C. West
Publication year - 1990
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/18.19.5633
Subject(s) - holliday junction , endonuclease , biology , branch migration , dna , cleave , recombinant dna , recombination , genetic recombination , escherichia coli , homologous recombination , homing endonuclease , biophysics , microbiology and biotechnology , genetics , gene
T7 endonuclease I is known to bind and cleave four-way junctions in DNA. Since these junctions serve as analogues of Holliday junctions that arise during genetic recombination, we have investigated the action of T7 endonuclease I on recombination intermediates containing Holliday junctions. We find that addition of T7 endonuclease I to strand exchange reactions catalysed by RecA protein of Escherichia coli leads to the formation of duplex products that correspond to 'patch' and 'splice' type recombinants. Resolution of the recombination intermediates occurs by the introduction of nicks at the site of the Holliday junction. The recombinant molecules contain 5'-phosphate and 3'-hydroxyl termini which may be ligated to restore the integrity of the DNA.