• BMB Reports
• /
• v.53 no.1
• /
• pp.3-9
• /
• 2020

The mitochondrial genome encodes 13 proteins that are components of the oxidative phosphorylation system (OXPHOS), suggesting that precise regulation of these genes is crucial for maintaining OXPHOS functions, including ATP production, calcium buffering, cell signaling, ROS production, and apoptosis. Furthermore, heteroplasmy or mis-regulation of gene expression in mitochondria frequently is associated with human mitochondrial diseases. Thus, various approaches have been developed to investigate the roles of genes encoded by the mitochondrial genome. In this review, we will discuss a wide range of techniques available for investigating the mitochondrial genome, mitochondrial transcription, and mitochondrial translation, which provide a useful guide to understanding mitochondrial gene expression.

• Animal cells and systems
• /
• v.3 no.3
• /
• pp.295-301
• /
• 1999

The nucleotide sequence of a 447 base pair fragment in the mitochondrial cytochrome b gene and the complete sequence of the mitochondrial 12S ribosomal RNA gene, 938 bp, were analyzed to infer inter- and intraspecific genetic relationships of Hyla japonica and H. suweonensis from Korea and H, japonica from Japan. In the mitochondrial cytochrome b gene, genetic differentiation among H. japonica populations were 9.62% and 15.66% between H. japonica and H. suweonensis. Based on the Tamura-Nei distance, the level of sequence divergence ranged from 0.45% to 2.75% within Korean H. japonica, while 8.31%-8.87% between Korean and Japanese H. japonica and 11.51%-12.46% between H. japonica and H. suweonensis. In the neigh-bor-joining tree, Korean populations of H. japonica were clustered first at 2.22% and followed by Japanese H. japonica and H. suweonensis at 8.51% and 12.29%, respectively. In mitochondrial 12S rRNA gene, genetic differentiation between H. japonica and H. suweonensis nras 7.17% (68 bp) including 7 gaps. Based on Tamura-Nei distance, the level of sequence divergence ranged 3.53% between Korean and Japanese H. japonica and from 4.93% to 5.41% between H. japonica and H. suweonensis. Phenogram pattern of the 12S rRNA gene sequence corresponded with that of the mitochondrial cytochrome b gene.

• Animal Systematics, Evolution and Diversity
• /
• v.26 no.3
• /
• pp.197-201
• /
• 2010

We sequenced the whole mitochondrial genome of Dendronephthya gigantea (Anthozoa: Octocorallia: Nephteidae), the first mitochondrial genome sequence report in the Family Nephtheidae. The mitochondrial genome of D. gigantea was 18,842 bp in length, and contained 14 protein coding genes (atp6 and 8, cox1-3, cytb, nd1-6 and 4L, and msh1), two ribosomal RNAs, and only one transfer RNA. The gene content and gene order is identical to other octocorals sequenced to date. The portion of the noncoding regions is slightly larger than the other octocorals (5.08% compared to average 3.98%). We expect that the information of gene content, gene order, codon usage, noncoding region and protein coding gene sequence could be used in the further analysis of anthozoan phylogeny.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.2 no.1
• /
• pp.1-6
• /
• 2001

This paper reports a few characteristics of seven insect mitochondrial genomes sequenced completely (Bombyx mori, Drosophila melanogaster, D. yakuba, Apis mellifera, Anopheles gambiae, A. quadrimaculatus, and Locusta migratoria). Comparative analysis of complete mt genome sequences from several species revealed a number of interesting features (base composition, gene content, A+T-rich region, and gene arrangement, etc) of insect mitochondrial genome. The properties revealed by our work shed new light on the organization and evolution of the insect mitochondrial genome and more importantly open up the way to clearly aimed experimental studies for understanding critical roles of the regulatory mechanisms (transcription and translation) in mitochondrial gene expression.

• Journal of Microbiology
• /
• v.35 no.3
• /
• pp.228-233
• /
• 1997

The MTF1 gene of Saccharomyces cerevisiae encodes a 43 kDa MITOCHONDRIAL RNA polymerase specificity factor which recognizes mitochondrial promoters to initiate correct transcription. To better understand structure-function of the MTF1 gene as well as the transcription mechanism of mitochondrial RNA polymerase, two cold-sensitive alleles of the MTF1 mutation were isolated by plasmid shuffling method after PCR-based random mutagenesis of the MTF1 gene. The mutation sites were analyzed by nucleotide sequencing. These cs phenotype mtf1 mutants were respiration competent on the nonfermentible glycerol medium at the permissive temperature, but incompetent at 13.deg.C. The cs phenotype allele of the MTF1, yJH147, encoded an L146P replacement. The other cs allele, yJH148, contained K179E and K214M double replacements. Mutations in both alleles were in a region of Mtflp which is located between domains with amino acid sequence similarities to conserved regions 2 and 3 of bacterial s factors.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.9
• /
• pp.1335-1340
• /
• 2006

It has been found that a number of diseases are associated with mutations in the mitochondrial DNA. Therapeutic gene delivery to mitochondria has been suggested as a clinical option for these diseases. In this study, we developed a gene carrier to mitochondria by the conjugation of mitochondrial leader peptide (LP) to polyethylenimine (PEI). Mitochondrial LP conjugated PEI (PEI-LP) was synthesized with low molecular weight PEI (2,000 Da, PEI2K). Gel retardation assay showed that PEI2K-LP formed complexes at a 1.0/1 weight ratio. In addition, PEI2K-LP protected DNA from the enzymatic degradation for at least 60 min, while naked DNA was completely degraded within 20 min. PEI2K-LP was compared with LP conjugated high molecular weight PEI (25,000 Da, PEI25K) in terms of toxicity and delivery efficiency. MTT assay showed that PEI2K-LP had much lower cytotoxicity than PEI25K-LP to 293 cells. In addition, cell-free DNA delivery assay showed that PEI2K-LP delivered more DNA to mitochondria at a 1.8/1 weight ratio than naked DNA or PEI. This result suggests that PEI2K-LP may be useful for the development of mitochondrial gene therapy system with lower cytotoxicity.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.24 no.1
• /
• pp.41-47
• /
• 2012

The Scarites aterrimus (Coleoptera: Carabidae) dwells exclusively on coastal sandy dunes. Previously, we investigated the nation-wide magnitude and nature of genetic diversity of the species using mitochondrial COI gene and found moderate to low magnitude of sequence diversity, the presence of closely related haplotypes, and relatively high gene flow estimate. Based on these observations we concluded that the species had no historical barriers that bolster genetic subdivision and possible population decline. In this study, we additionally sequenced mitochondrial COII gene from 23 individuals collected from 9 Korean localities to confirm previous findings. Sequencing of 688 bp COII gene provided 5 haplotypes ranging in sequence divergence from 0.145% to 0.291% (1 ~ 2 bp), further confirming low sequence divergence of the species. Gene flow estimates and genetic diversity estimates also support the previous findings that there had been no historical barriers that bolster genetic subdivision.

• Journal of Embryo Transfer
• /
• v.25 no.1
• /
• pp.35-42
• /
• 2010

Many studies propose that dysfunction of mitochondrial proton-translocating NADH-ubiquinone oxidoreductase (complex I) is associated with neurodegenerative disorders, such as Parkinson's disease and Huntington's disease. Mammalian mitochondrial proton-translocating NADH-quinone oxidoreductase (complex I) consists of at least 46 different subunits. In contrast, the NDI1 gene of Saccharomyces cerevisiae is a single subunit rotenone-insensitive NADH-quinone oxidoreductase that is located on the matrix side of the inner mitochondrial membrane. With a recombinant adeno-associated virus vector carrying the NDI1 gene (rAAV-NDI1) as the gene delivery method, we were able to attain high transduction efficiencies even in the human epithelial cervical cancer cells that are difficult to transfect by lipofection or calcium phosphate precipitation methods. Using a rAAV-NDI1, we demonstrated that the Ndi1 enzyme is successfully expressed in HeLa cells. The expressed Ndi1 enzyme was recognized to be localized in mitochondria by confocal immunofluorescence microscopic analyses and immunoblotting. Using digitonin-permeabilized cells, it was shown that the NADH oxidase activity of the NDI1-transduced HeLa cells were not affected by rotenone which is inhibitor of complex I, but was inhibited by flavone and antimycin A. The NDI1-transduced cells were able to grow in media containing rotenone. In contrast, control cells that did not receive the NDI1 gene failed to survive. In particular, in the NDI1-transduced cells, the yeast enzyme becomes integrated into the human respiratory chain. It is concluded that the NDI1 gene provides a potentially useful tool for gene therapy of mitochondrial diseases caused by complex I deficiency.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.35 no.1
• /
• pp.51-57
• /
• 2017

The tiny dragonfly, Nannophya pygmaea (Odonata: Libellulidae), is an endangered insect in South Korea. Previously, a partial mitochondrial DNA sequence that corresponded to a DNA barcoding region has been used to infer genetic diversity and gene flow. In this study, we additionally sequenced the barcoding region from N. pygmaea that had been collected from three previously sampled populations (40 individuals) and these sequences were combined with the preexisting data. We also selected and sequenced an additional mitochondrial gene (ND5) to find further variable gene regions in the mitochondrial genome. DNA barcoding sequences of 108 individuals from five South Korean localities showed that genetic diversity was highest in Gangjin, Jeollanam-do Province. Muuido, which was previously occupied by a single haplotype, was also found to have an identical haplotype, which confirmed the low genetic diversity on this islet. Gene flow among populations is highly limited, and no clear distance- or region-based geographic partitioning was observed. Phylogenetic relationships among haplotypes showed that there were no discernable haplotypes in South Korea. ND5 provided slightly more haplotypes compared to the barcoding region in 40 individuals (14 vs. 10 haplotypes in the COI gene). It also had a slightly higher within-locality diversity estimate, which suggested that ND5 had potential as mitochondrial DNA-based marker for population genetic analysis.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2007.04a
• /
• pp.147-153
• /
• 2007

Central to developing new treatment strategies for late onset sporadic Parkinson's disease (PD) and early onset familial PD is resolving the enigma of the specific vulnerability exhibited by substantia nigra dopamine (DA) neurons despite multiple risk factors. Neuropathological evidence from both human and experimental models of PD firmly supports a significant role for oxidative stress (OS) and mitochondrial dysfunction in the death of nigral DA neurons. Largely unknown are the genes underlying selective susceptibility of nigral DA neuron to OS and mitochondrial dysfunction and how they effect nigral DA cell death. To overcome the paucity of nigral DA neurons as well as the dilution effect of non-DA cells in brain tissues, we have developed wild type DA cell line model, SN4741 and mutant DJ-1 (-/-) DA cells, appropriate for microarray analysis and differential mitochondrial proteomics. Mutations in the DJ-1 gene (PARK7), localized in cytoplasm and mitochondria, cause autosomal recessive early onset PD. Through microarray analysis using SN4741 cells followed by validation tests, we have identified a novel phylogenically conserved neuroprotective gene, Oxi-a, which is specifically expressed in DA neurons. The knockdown of the gene dramatically increased vulnerability to as. Importantly as down-regulated the expression level of the gene and recovery of its expression via transient transfection exerted significant neuroprotection against as insult. We also have identified altered expression of mitochondrial proteins and other familial PD genes in DJ-1 (-/-) mutant cells by differential mitochondrial proteomics. In DJ-1 (-/-) cells the knockdown of the other familial PD genes (Parkin and PINK1) dramatically increased susceptibility to as. Thus, further functional characterization of the Oxi-$\alpha$ gene family and the mitochondrial alteration in the DJ-1 (-/-) cell model will provide the rationale for the neuroprotective therapy against both sporadic and familial PD.