• Journal of Life Science
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• v.31 no.12
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• pp.1057-1065
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• 2021

Alterations in mitochondrial DNA (mtDNA) copy numbers have been reported in patients with stomach cancer and suggested to play a role in gastric carcinogenesis or gastric cancer progression. However, changes in the levels of mitochondrial proteins or mtDNA-encoded oxidative phosphorylation (OXPHOS) proteins in gastric cancer remain unclear. In this study, we investigated mtDNA contents, mitochondrial protein levels, and mtDNA-encoded OXPHOS protein levels in gastric cancer tissues and cell lines. We correlated mtDNA copy numbers with clinicopathologic features of the gastric cancer samples used in this study and used quantitative PCR to analyze the mtDNA copy numbers of the gastric cancer tissues and cell lines. Western blot analysis was used for assessing the amounts of mitochondrial proteins and mtDNA-encoded OXPHOS proteins. Among the 27 gastric cancer samples, 22 showed a reduction in mtDNA copy numbers. The mtDNA content was increased in the other five samples relative to that in normal matched gastric tissues. Mitochondrial protein and OXPHOS protein levels were reduced in some gastric cancer tissues. However, mitochondrial protein and OXPHOS protein levels in gastric cancer cell lines were not always in line with their mtDNA contents. The mtDNA copy numbers were reduced in five gastric cancer cell lines tested in this study. In summary, this study reports a common reduction in mtDNA contents in gastric carcinoma tissues and cell lines, pointing to the possible involvement of mtDNA content alterations in tumorigenesis of the stomach.

• Animal Systematics, Evolution and Diversity
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• v.9 no.2
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• pp.171-179
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• 1993

Thirty nine samples of striped field mice (Apodemus agrarius coreae Thomas) from eight localities in the Korean peninsula were used for the analyses of mitochondria1 DNA (mtDNA) fragment patterns resulted from the digestion with eight restriction enzymes. A total of 31 fragments were recognized and seven mtDNA clones were revealed: one clone consisted of 32 among 39 samples from eight localities (1 of 1 from Sogcho, 4 of 5 from Mt. Chiak, 3 of 3 from Mt. Weolak, 2 of 2 from Mt. Sogri, 2 of 2 from Mt. Deokyoo, 3 of 4 from Mt. Jiri, 2 of 4 from Haenam, and 15 of 18 from Cheongju). The nucleotide-sequence divergences (p) among seven mtDNA clones ranged from 0.2% to 2.3% and distinct subgroups were not resulted from the grouping of these clones. It is confirmed that striped field mcie from the Korean peninsula is a single subspecies of Apodemus agrarius (A. agrarius coreae) because they were not divided into separate subgroups in their mtDNA genotypes.

• Korean journal of applied entomology
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• v.29 no.2
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• pp.132-135
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• 1990

Three mitochondrial cDNA probes from Aedes albopictus were used to demonstrate restriction site polymorphism in mtDNA of three sibling species of Anopheles quadrimaculatus(Say). It was shown by DNA hybridization to have substantial sequence homology betwen the mtDNA of different genus. The proves reveled local restriction site variation between members of the Anopheles quadrimaculatus sibling species complex. Mitochondrical DNA (mtDNA), isolated from individual mosquitoes was digested by type II restriction enzymes and four enzymes were found to be useful for the purpose. Hind III alone could be used to obtain a diagnostic restriction pattern.

• Animal Systematics, Evolution and Diversity
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• v.11 no.2
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• pp.291-299
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• 1995

Sampels of Korean field mice (apodemus peninsulae peninsulae Thomas ) from six localities in Korea were used for the analyses of mitochondrial DNa (Mt DNA) fragment patterns resulted from the digestion with eight restriction enzymes. A total of 29 fragments were recognized and seven mtDNA clones were revealed. The nucleotide-sequence divergences (p) among the seven mtDNA clones ranged from 0.42% to 2.01%. Moreover, the seven clones were grouped into three major subgroups with the mean divergence value of 1.52% among them. One subgroup was composed of three clones of 18 sample from three localities (16, Cheongu: 1, Mt. Sobaek : 1, Mt. weolak) L another subgroup, three clones of eight samples from four localities (2, Cheongju ; 2 , Mt. Weolak ; 2, Mt. Gaya ; 2, haenam) ; and the last subgroup, one clone of two samples from Cheongju. Three subgroups were also distinct with one another in their mtDNA genotypes of Stu I and the former two subgroups differed from the last subgroup in their genotypes with Pvu II. Further analyses with additional samples from various localities in Korea appeared to be necessary in order to clarify the taxonomic status of the distinct mtDNA subgroups.

• BMB Reports
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• v.57 no.1
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• pp.19-29
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• 2024

Mitochondrial DNA (mtDNA), a multicopy genome found in mitochondria, is crucial for oxidative phosphorylation. Mutations in mtDNA can lead to severe mitochondrial dysfunction in tissues and organs with high energy demand. MtDNA mutations are closely associated with mitochondrial and age-related disease. To better understand the functional role of mtDNA and work toward developing therapeutics, it is essential to advance technology that is capable of manipulating the mitochondrial genome. This review discusses ongoing efforts in mitochondrial genome editing with mtDNA nucleases and base editors, including the tools, delivery strategies, and applications. Future advances in mitochondrial genome editing to address challenges regarding their efficiency and specificity can achieve the promise of therapeutic genome editing.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.6
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• pp.519-528
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• 2019

Mitochondrial dysfunction is closely associated with reactive oxygen species (ROS) generation and oxidative stress in cells. On the other hand, modulation of the cellular antioxidant defense system by changes in the mitochondrial DNA (mtDNA) content is largely unknown. To determine the relationship between the cellular mtDNA content and defense system against oxidative stress, this study examined a set of myoblasts containing a depleted or reverted mtDNA content. A change in the cellular mtDNA content modulated the expression of antioxidant enzymes in myoblasts. In particular, the expression and activity of glutathione peroxidase (GPx) and catalase were inversely correlated with the mtDNA content in myoblasts. The depletion of mtDNA decreased both the reduced glutathione (GSH) and oxidized glutathione (GSSG) slightly, whereas the cellular redox status, as assessed by the GSH/GSSG ratio, was similar to that of the control. Interestingly, the steady-state level of the intracellular ROS, which depends on the reciprocal actions between ROS generation and detoxification, was reduced significantly and the lethality induced by $H_2O_2$ was alleviated by mtDNA depletion in myoblasts. Therefore, these results suggest that the ROS homeostasis and antioxidant enzymes are modulated by the cellular mtDNA content and that the increased expression and activity of GPx and catalase through the depletion of mtDNA are closely associated with an alleviation of the oxidative stress in myoblasts.

• The Korean Journal of Zoology
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• v.31 no.3
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• pp.218-224
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• 1988

Restriction endonucleases were used to search for intraspecific variation at 32 cleavage sites in mitochondrial DNA(mtDNA) purified from fourteen strains of Drosophila melanogaster helonging to different localities of the world. mtDNA of D. melanogaster was displayed site variation(Hpall, Haelll and Seal endonucleases) and length variation(maxirnum 550bp). Six genotypes, Ml, M2, M3, M4, M6 and M7, could be distinguished based on ihe site types witti a low average of intraspecific substitution rate (1.88%),but M5 type of Ogasawara strain in Japan was not detected in this study. A possible explanation for the low divergence was that mtDNA variation of fourteen strains in D. melanogaster could not he accumulated sufficiently owing to recent divergence of few individuals, and that sequence divergence was prevented by frequent migration in spite of the geographical isolation.

• Journal of Applied Biological Chemistry
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• v.57 no.3
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• pp.259-265
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• 2014

Mitochondrial DNA (mtDNA)-depleted (${\rho}^0$) cells are often used as mtDNA recipients to study the interaction between the nucleus and mitochondria in mammalian cells. Therefore, it is crucial to obtain mtDNA-depleted cells with many different nuclear backgrounds for the study. Here, we demonstrate a rapid and reliable method to isolate mammalian mtDNA-depleted cells involving treatment with the antimitochondrial agents ethidium bromide (EtBr) and 2',3'-dideoxycytidine (ddC). After a short exposure to EtBr or ddC, followed by rapid clonal isolation, we were able to generate viable mtDNA-depleted cells from mouse and human cells and were able to successfully repopulate them with exogenous mitochondria from platelets isolated from mouse and human blood samples. These mtDNA-depleted cells can be used to characterize the nuclear mitochondrial interactions and to study mtDNA-associated defects in mammalian cells. Our method of isolating mtDNA-depleted cells is practical and applicable to a variety of cell types.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.218-225
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• 2005

This study was performed to determine sequence variation and RFLP of the mt DNA D-loop region using Southern blot hybridization analysis and to develop mt DNA marker affecting milk production traits in Hanwoo cows. The PCR was used to amplify an 1142 bp fragment within the D-loop region of mt DNA using specific primers. Mt DNA were digested with seven restriction enzymes and hybridized using DIG-labeled D-loop probe. The mt DNA RFLP polymorphisms were observed in the four enzymes, BamHI, RsaI, XbaI and HpaII. Nucleotide substitutions were detected at positions 441 (G/C), 469 (T/C), 503 (C/T), 569 (G/A), 614 (C/A) and 644 (C/T) of the mt DNA D-loop region between two selected lines. Significant relationship between the XbaI RFLP type and breeding value was found(p<0.05). Cows with A type had higher estimated breeding values than those with B type (P<0.05) between high and low milk production lines. Therefore, the RFLP marker of mt DNA could be used as a selection assisted tool for individuals with high milk producing ability in Hanwoo.

• Korean journal of applied entomology
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• v.37 no.1
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• pp.23-30
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• 1998

Restriction fragment length polymorphism (RFLP) of a DNA has been a useful tool for analyzing genetic variation. This research was performed to establish an RFLP analytic method on the mitochondrial DNA (mtDNA) of the beet armyworm, Spodoptera exigua (Hiibner). To do this, total size of the mtDNA was measured and polymerase chain reaction (PCR) primers were selected. Its mitochondrial genome size was ca. 16kb. From a serial PCR test of 29 primers refered to the compilation of Simon et al. (1994), 22 primers were selected to amplify its mtDNA fragments. These primers resulted in short (300-700 bp) or long (1000-2000 bp) DNA products which represented a total or partial sequence of each of CO-I, CO-11, Cyt-B, ND-1, 12s rRNA, 16s rRNA, and some tRNAs. PCR-RFLP was performed in some variable mtDNA regions with 8 kinds of 4bp recognizing restriction enzymes. Different populations from Andong, Kyungsan, and Sunchun did not show any restriction site polymorphisms but had some length variation in certain regions of mtDNA.