Study On The Location And Function Of Mpa1 In Schizosaccharomyces Pombe

Mitochondria are involved in oxidative metabolism, final oxidation of carbohydrates, fats and amino acids in eukaryotes. Mitochondria are the main place of cellular oxidative phosphorylation and synthesis of adenosine triphosphate (ATP), and can provide energy for cell, so they are called "power plants". In addition, mitochondria have their own genome which encodes a limited number of genes. Therefore, mitochondria are only semi-autonomous organelles.The disorders of mitochondrial gene expression lead to various diseases, and how to treat mitochondrial diseases has become the focus of the current study. Many studies show that mitochondrial dysfunction is closely related to the development and progression of Parkinson’s disease, Alzheimer’s disease, diabetes, and cancer. Mitochondrial dysfunction is not only the cause of above diseases, but also is associated with early signs of those diseases. Study of the expression mechanism of the mitochondrial genes can offer help for the treatment of mitochondrial diseases.Through the tandem affinity purification, co-immunoprecipitation experiment, mass spectrometry technique, our laboratory has revealed that there is an interaction between Ppr10 and Mpal in vivo, mpal is a novel gene. In this study we will characterize the functions of Mpal.Ppr10 contains a mitochondrial localization signal predicated by MitoProtⅡ (https://ihg.gsf.de/ihg/mitoprot.html), whereas Mpal does not. We determined the subcellular localization of Mpal, a novel Ppr10-associated protein, and found that Mpal is localized in the mitochondrial matrix.Firstly, we deleted the mpal gene in a haploid strain and found that Ampal cells are viable, indicating that it is a nonessential gene. Then we examined phenotypes of mpal gene deletion mutant, including growth, cell morphology, viability and the sensitivity of cells to the mitochondrial respiratory chain inhibitor, antimycin A. Phenotypic study showed that the mpal deletion mutant strain exhibits growth defects in respiratory media, and is dramatically impaired for viability during the late-stationary phase. These results indicated that Ampal cells are deficient in mitochondrial respiration. Western Blot analysis also showed that deletion of mpal severely impairs mitochondrial protein synthesis..Finally, we constructed the △mpo1/pJK148-1500-mpa1-3HA strain in which mpal is under control of its own promoter and is integrated in the leu1-32 locus. We can detect the normal expression of Mpa1 by Western Blotting. Integration of mpa1 can rescue growth defects of △mpa1 and can recover mitochondrial protein synthesis in △mpa1 cells. This experiment can verify that mpa1 is a nonessential gene. Based on this, we study the function of different parts of Mpa1. No matter which part of Mpa1 is lost, we can detect the normal expression of Mpa1, but it can not make up the growth defects in respiratory media. This indicates that Mpa1 can perform functions only in the case of structural integrity.