title: Endo.SK1: an inducible site-specific endonuclease from yeast mitochondria.
abstract: Site-specific endonucleases have been found in various eukaryotic organelles such as mitochondria, chloroplasts and nuclei. These endonucleases initiate site-specific or homologous gene conversion in mitochondrial and nuclear DNA. Here, we report a new site-specific endonuclease activity, Endo.SK1, identified in mitochondria of strain SK1, a homothallic diploid strain of Saccharomyces cerevisiae. Nucleotide sequences around the Endo.SK1-cleavage sites are different from those of known yeast site-specific endonucleases. The Endo.SK1 activity is, at least partly, specified by a gene in the SK1-derived mitochondria. A novel feature of the Endo.SK1 activity is its inducibility: the endonuclease activity was induced by ca. 40-fold by transfer of cells from a glucose medium into an acetate medium, and was then repressed. This transient induction was independent of the ploidy level of the cells, and coincided with induction of fumarase, a mitochondrial enzyme involved in the TCA cycle. Co-induction and co-repression of the mitochondrial site-specific endonuclease activity and a respiration-related enzyme indicate that the endonuclease activity in regulated in response to physiological conditions, and suggest a possible role for the endonuclease in mitochondrial DNA metabolism.
authors.affiliation: Laboratory of Cellular and Molecular Biology, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ohta
authors.forename: A
authors.initials: A
authors.lastname: Nicolas
authors.forename: D
authors.initials: D
authors.lastname: Keszenman-Pereyra
authors.forename: T
authors.initials: T
authors.lastname: Shibata
mesh_terms: D017103:Bacillus Phages; D001483:Base Sequence; D004279:DNA, Viral / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000096:biosynthesis / Q000378:metabolism*; D004790:Enzyme Induction; D008928:Mitochondria / Q000201:enzymology*; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000502:physiology; D013172:Spores, Fungal; D013379:Substrate Specificity
chemical_list: D004279:DNA, Viral; D004706:Endodeoxyribonucleases