Formation of Double-strand Break in DNA by SPO11 Authored: May, B, 2010-07-19 EC Number: 3.1.21 Edited: May, B, 2010-07-19 Reactome Database ID Release 43912368 Reactome, http://www.reactome.org ReactomeREACT_27239 Reviewed: Bolcun-Filas, E, 2011-02-25 Reviewed: Cohen, PE, 2011-02-04 Reviewed: Holloway, JK, 2011-02-04 Reviewed: Lyndaker, A, 2011-02-25 Reviewed: Schimenti, JC, 2011-02-04 Reviewed: Strong, E, 2011-02-25 The gene encoding SPO11 shares sequence similarity to TopoVI, a type II topoisomerase. SPO11 dimers cleave both strands of DNA. Each subunit of the dimer remains covalently attached to the 5' end of one strand of DNA via a phosphodiester linkage to a conserved tyrosine residue of SPO11. In addition to SPO11, work from budding yeast has shown a total of 7 proteins essential for double strand break formation. The mammalian ortholog of Mei4 (S. cerevisiae) as well as a mammalian-specific gene called Mei1 are essential to formation of meiotic double strand breaks. SPO11 Covalently Attached to Double-strand Break SPO11 Dimer DNA