2C-08 Intracellular localization of the plant tRNA splicing endonuclease

Eukaryotic precursor tRNAs containing introns are processed in the nucleus and the mature forms of tRNAs are imported into the cytoplasm. It has been shown in yeast that tRNA introns are removed by tRNA splicing endonuclease complex that is located in the inner membrane of the nuclear envelope. Surprisingly, the latest study has revealed that the yeast endonuclease is predominantly located on the outer membrane of mitochondria. In order to explore an intracellular localization of the plant tRNA endonuclease, two different kinds of GFP fusion genes (i. e., AtSen1：：GFP and AtSen2：：GFP) were constructed based on the Arabidopsis genes coding for the splicing endonuclease subunits. These plasmids were introduced into the onion epidermal cells with a particle gun. Green fluorescent signals were observed not only in the nucleus but also in the discrete dot-like structures.