Abstract
In plants and algae, organellar genomes are replicated by POPs(plant organellar DNA polymerases). In a previous annual meeting, we reported that POP purified from the cells of rhodophyte Cyanidioschyzon showed high processivity and severely inhibited by phosphonoacetate. POPs are widely conserved in eukaryotes except metazoa and fungi. A ciliate Tetrahymena has a single POP gene. Tetrahymena does not have a chloroplast, but it is thought to be a plant in a wide sense (Plantae) (Nozaki, 2003). There are a few studies about mitochondrial DNA polymerase in Tetrahymena, but detailed analysis was not performed. The purpose of this study is purification of POP from Tetrahymena cells and comparison of the enzymatic activities of POP between Tetrahymena and Cyanidioschyzon. Immunoblotting showed that Tetrahymena POP was localized to mitochondria. Phosphonoacetate strongly inhibited the DNA synthesis activity of Tetrahymena mitochondria. These results suggested that inhibition by phosphonoacetate is a common property of POPs.
