title: A mechanism to activate branch migration between homologous DNA molecules in genetic recombination.
abstract: A mechanism to activate branch migration between homologous DNA molecules is described that leads to synapsis in genetic recombination. The model involves a restriction-like endonucleolytic enzyme that first nicks DNA (to produce single-strand breaks) on strands of opposite polarity at symmetrically arranged nucleotide sequences (located at ends of genes or operons). This is followed by local denaturation of the region, promoted by a single-strand-specific DNA binding protein (i.e., an unwinding protein). Hydrogen-bounding between homologous DNA molecules can then be initiated and this allows for subsequent propagation of hybrid DNA in the pathway to formation of the synapton structure.
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D005796:Genes; D008540:Meiosis; D008954:Models, Biological; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009711:Nucleotides / Q000032:analysis; D009876:Operon; D010641:Phenotype; D011119:Polynucleotides / Q000032:analysis; D011831:Radiation Genetics; D011995:Recombination, Genetic
chemical_list: D004277:DNA, Single-Stranded; D009711:Nucleotides; D011119:Polynucleotides; D004247:DNA; D004720:Endonucleases