title: A new meiotic endonuclease from Coprinus meiocytes.
abstract: Two different types of Coprinus meiotic nuclease have been previously reported by the authors which are believed to be involved in meiotic chromosome recombination [1,2]. A third meiotic endonuclease was purified from the cap tissues of the basidiocarp of Coprinus cinereus. The enzyme is a 60 kDa molecule composed of a monopolypeptide as revealed by SDS-PAGE and FPLC-Sephacryl S-300 gel filtration. The enzyme belongs to a type of endonuclease which can preferentially digest single-stranded DNA and requires divalent cations as a co-factor, most commonly Mg2+ ions. In the presence of this co-factor, the enzyme converts the supercoiled plasmid DNA (form I) to both the relaxed form (form II) and the linear form (form III). Ca2+ ions can also function as a co-factor, though, in this case, not only is form I plasmid converted to form II, but a few ladder bands between form I and form II are also produced. The Ca2+ ion effect as a cofactor can be prevented with ATP. Immunohistochemical observation shows that the enzyme is distributed in the surface of the gills, which contain the meiotic tissues. These characteristics clearly differ from those of the meiotic nucleases reported previously.
authors.affiliation: Department of Applied Biological Science, Faculty of Science and Technology, Science University of Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kitamura
authors.forename: Y
authors.initials: Y
authors.lastname: Kouroku
authors.forename: M
authors.initials: M
authors.lastname: Onoue
authors.forename: S
authors.initials: S
authors.lastname: Kimura
authors.forename: M
authors.initials: M
authors.lastname: Takenouchi
authors.forename: K
authors.initials: K
authors.lastname: Sakaguchi
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D003302:Coprinus / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007150:Immunohistochemistry; D008540:Meiosis; D008970:Molecular Weight; D051381:Rats; D013379:Substrate Specificity
chemical_list: D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D004706:Endodeoxyribonucleases; C078472:mENase protein, Coprinus cinereus