Localization Of Ppr10 Protein In Schizosaccharomyces Pombe And Its Effects On Mitochondrial Proteins

Mitochondria is one of the very important organelles in eukaryotes, which is involved in the synthesis of ATP and a variety of physiological processes like metabolism and apoptosis. As a model organism in eukaryotic, fission yeast (Schizosaccharomyces pombe, S. Pombe) is widely used in the mitochondrial transcription and translation. As a model for mitochondrial research, the advantages of fission yeast are receiving greater attention.The process of the mitochondrial genome transcription is firstly forming poly-cistron, through shearing process, then forming mature RNA. Among diverse organisms, PPR protein is involved in the mitochondrial genome transcription and translation processes. PPR protein refers to a protein containing two or more tandem repeats of the PPR motif, while PPR motif consists of 35 amino acid residues. PPR protein having a specific simple-chain RNA recognition mode, and is closely related to RNA transcription, editing, cutting and stability. Mitochondrial genome of S. pombe encodes 25 kinds of tRNA,8 kinds of mRNA,2 kinds of rRNA and a rnpB.In this work, we studied the role of a PPR protein in mitochondria. Ppr10 is a recently discovered PPR protein, The ppr10 deletion mutant strain grows a little slow in complete medium and exhibits growth defects in complete medium containing antimycin A. This suggests that Ppr 10 is closely related to mitochondrial function. Collectively, we firstly found that Ppr10 is located in mitochondria, and is located inside the mitochondria and it is a soluble protein. Ppr proteins are a class of RNA binding proteins, which are mainly involved in mitochondrial genome transcription and translation, According to this feature of PPR protein, we think that Ppr10 is more likely to locate in the mitochondrial matrix. Secondly, we found that with the exception of Cobl, the deletion of ppr10 causes a severe reduction in all the synthesis of mitochondrial proteins, especially Coxl, Cox2 and Atp8,9. Western blot analysis experiment tells us that when ppr 10 is deleted, the level of mitochondrial proteins Coxl, Cox2, Cox3, Cobl is sharply declined, barely detectable. Since ppr10 deletion affects the protein synthesis which is encoded by mitochondrial genome, but also makes Cobl become extremely unstable, then the protein called Cox4 which is a nuclear genome encoded protein and participates in the constitution of complex IV, what happens to it? We expressed Cox4, and obtained the corresponding antibody. By Western blot analysis experiment, we found that the level of protein Cox4 has been reduced. Thus, we suggest that Ppr10 protein is closely related to the function of mitochondria. Through influencing the synthesis of proteins encoded by mitochondrial, it broke down the complexes in respiratory chain, leading to the lack of mitochondrial function.