bims-cytox1 Biomed news
on Cytochrome oxidase subunit 1
Issue of 2018‒09‒16
two papers selected by
Gavin McStay
Staffordshire University

  1. Mitochondrion. 2018 Sep 06. pii: S1567-7249(18)30114-4. [Epub ahead of print]
    Li D, Sun Y, Zhuang Q, Song Y, Wu B, Jia Z, Pan H, Zhou H, Hu S, Zhang B, Qiu Y, Dai Y, Chen S, Xu X, Zhu X, Lin A, Huang W, Liu Z, Yan Q.
      Hypertrophic cardiomyopathy (HCM), affecting approximately 1 in 500 in the general population, is the most prominent cause of sudden heart disease-related mortality in the young. Mitochondrial DNA (mtDNA) mutations are among the primary causes of HCM. We previously identified a novel m.2336T>C homoplasmic mutation in the mitochondrial 16S rRNA gene (MT-RNR2) in a Chinese maternally inherited HCM family. However, the molecular mechanisms by which m.2336T>C mutation contributes to HCM remain elusive. Here we generated transferring mitochondria cell lines (cybrids) with a constant nuclear background by transferring mitochondria from immortalized lymphoblastoid cell lines carrying the HCM-associated m.2336T>C mutation into human mtDNA-less (ρ°) cells. Functional assays showed a decreased stability for 16S rRNA and the steady-state levels of its binding proteins in the mutant cybrids. This mutation impaired the mitochondrial translation capacity and resulted in many mitochondrial dysfunctions, including elevation of ROS generation, reduction of ATP production and impairment of mitochondrial membrane potential. Moreover, the mutant cybrids had poor physiological status and decreased survival ability. These results confirm that the m.2336T>C mutation leads to mitochondrial dysfunction and strongly suggest that this mutation may play a role in the pathogenesis of HCM.
    Keywords:  Hypertrophic cardiomyopathy; M.2336T>C mutation; MT-RNR2; Mitochondrion; Transferring mitochondria cell lines
  2. Biochemistry (Mosc). 2018 Jun;83(6): 643-661
    Verechshagina NA, Konstantinov YM, Kamenski PA, Mazunin IO.
      Many mitochondrial genes have been transferred to the nucleus in course of evolution. The products of expression of these genes, being still necessary for organelle function, are imported there from the cytosol. Molecular mechanisms of protein import are studied much deeper than those of nucleic acids. The latter, it seems to us, retards the development of mitochondrial genome editing technologies. In this review, we describe mechanisms of DNA, RNA, and protein import into mitochondria of different eukaryotes. The description is given for the natural processes, as well as for artificial targeting of macromolecules into mitochondria for therapy. Also, we discuss different approaches to introduce changes into the mitochondrial DNA sequence.