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.
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Nucleic Acids Res
January 2025
Research Center for Life Sciences Computing, Zhejiang Lab, Kechuang Avenue, Yuhang District, Hangzhou, Zhejiang, 311121, China.
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January 2025
Department of General Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
The RNase activity of MCPIP1 is essential for regulating cellular homeostasis, proliferation, and tumorigenesis. Our study elucidates the effects of downregulation of MCPIP1 expression and an RNase-inactivating mutation (D141N) on normal epithelial kidney cells, indicating that MCPIP1 expression is a key factor that suppresses neoplastic transformation. We observed that either expression downregulation or mutation of MCPIP1 significantly increased its clonogenicity and altered the expression of cancer stem cell (CSC) markers and factors involved in epithelial-to-mesenchymal transition (EMT).
View Article and Find Full Text PDFACS Nano
January 2025
Bragg Centre for Materials Research, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, U.K.
The field of nanopore sensing is now moving beyond nucleic acid sequencing. An exciting avenue is the use of nanopore platforms for the monitoring of biochemical reactions. Biological nanopores have been used for this application, but solid-state nanopore approaches have lagged.
View Article and Find Full Text PDFAnal Chem
January 2025
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, PR China.
An entropy-driven catalysis (EDC) strategy is appealing for amplified bioimaging of microRNAs in living cells; yet, complex operation procedures, lacking of cell selectivity, and insufficient accuracy hamper its further applications. Here, we introduce an ingenious all-in-one entropy-driven DNA nanomachine (termed as AIO-EDN), which can be triggered by endogenous apurinic/apyrimidinic endonuclease 1 (APE1) to achieve tumor cell-selective dual-mode imaging of microRNA. Compared with the traditional EDC strategy, the integrated design of AIO-EDN achieves autocatalytic signal amplification without extra fuel strands.
View Article and Find Full Text PDFMikrochim Acta
January 2025
School of Public Health, Jilin University, Changchun, Jilin, 130021, P. R. China.
A spherical nucleic acid (SNA, AuNPs-aptamer) into CRISPR/Cas12a system combined with poly T-template copper nanoparticles as fluorescence reporter was fabricated to establish an amplification-free sensitive method for Staphylococcus aureus (S. aureus) detection. This method, named PTCas12a, utilizes the concept that the bifunction of SNA recognizes the S.
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