Open AccessOn the mechanism of genetic recombination: electron microscopic observation of recombination intermediates.
Author(s) -
Huntington Potter,
David Dressler
Publication year - 1976
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.73.9.3000
Subject(s) - recombination , colicin , dna , flp frt recombination , genetic recombination , cre lox recombination , biology , ecori , holliday junction , site specific recombination , plasmid , in vitro recombination , molecule , recombinant dna , genetics , chemistry , gene , molecular cloning , recombinase , complementary dna , transgene , genetically modified mouse , organic chemistry
This paper deals with the nature of recombination intermediates. Using the electron microscope to study the DNA of the plasmid colicin E1, we have observed more than 800 molecules that appear to represent intermediates in the process of recombination. Specifically, after isolating colicin DNA and linearizing it with the restriction enzyme EcoRI, we find crossed molecules with twice the normal colicin DNA content. These forms consist of two genome-length elements held together at a region of DNA homology. The molecules can be recovered from wild type and Rec B-C host cells but are not present among the colicin DNA forms isolated from recombination-deficient Rec A cells. We have termed the experimentally observed molecules "chi forms" and believe that they represent the recombination intermediate of the Holliday model.