Endo.SK1: an inducible site-specific endonuclease from yeast mitochondria.
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.
Ohta
K
K
Laboratory of Cellular and Molecular Biology, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
Nicolas
A
A
Keszenman-Pereyra
D
D
Shibata
T
T
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
D004279:DNA, Viral; D004706:Endodeoxyribonucleases