Study On The Effect Of Mtf2 Protein Of Schizosaccharomyces Pombe On The Translation Of MtDNA-encoded Protein

The mitochondria produce energy via oxidative phosphorylation,and they produce ATP through the respiratory chain complex electron transport chain.Mitochondria are semi-autonomous organelles that have their own genome.In,Schizosaccharomyces pombe,the expression of mitochondrial function in the mitochondrial genome is crucial to encode oxidative phosphorylation including 7 key subunits.Mtf2 has homologous protein Nam1 in Saccharomyces cerevisiae.It is reported that Nam1 is located in the mitochondrial matrix,participate in the mitochondrial genome encoding COX1,CYTB1 and ATP6 mRNA processing and stability.Nam1 for COX1 and CYTB introns splicing is necessary,and Nam1 protein synthesis of mitochondrial genome encoding is global impact.Through the previous experiments,we found that the growth of Amtf2 in non-fermentation medium was severely inhibited,and we speculated that Mtf2 protein was associated with mitochondrial function.Therefore,in this paper,we mainly studied the specific functions of Mtf2 protein in mitochondria.First,we found that the Mtf2 protein was a soluble protein that was located in the mitochondria.Secondly,by RT-qPCR and northern blot experiments,mtf2 deletion in a mitochondrial intron-containing background resulted in a barely detectable level of the cox1 mRNA and a reduction in the level of the cob1 mRNA,Mtf2 protein is essential for the accumulation of cox1 and cob1 mRNA encoded in the mitochondrial genome.Next,we found that Mtf2 affected the intron splicing of cox1 and cobl by RT-PCR.In contrast,mtf2 deletion in a mitochondrial intron-less background did not affect the levels of cox1 and cob1 mRNAs.However,Cox1 synthesis could not be restored to the control level in the ?mtf2 mutant with intron-less mtDNA.Finally,by western blot analysis experiment,we found that in the ?mtf2/P3 mutant,there is almost undetectable Cox1 and Cox3 protein,Cob1 and Cox2 protein steady-state level is significantly reduced,and nuclear gene encoding protein Cox4 steady-state level is only a slight drop.S.pombe Mtf2 primarily functions in cox1 mRNA translation and the effect of mtf2 deletion on splicing of introns in mtDNA is likely due to a deficiency in the synthesis of intron-encoded maturases.