Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.5.3 (complex I)
 8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By use of restriction fragment length polymorphism analysis, we examined the liver mitochondrial DNA amplified by polymerase chain reaction from 60 Chinese subjects of 31 to 78 years of age. We found nine specific mtDNA polymorphisms that had never been reported before. Eleven subjects had an Alu I polymorphic site in the subunit 2 gene of NADH dehydrogenase, five had a Hae III polymorphic site in the cytochrome oxidase subunit 2 gene, and five had a Hinf I polymorphic site in the subunit 3 gene of cytochrome oxidase. No polymorphic site was found in the structural genes coding for subunits 1, 3, 4, 4L and 6 of NADH dehydrogenase, cytochrome b, and subunit 8 of ATP synthase. Detailed analysis of the RFLP data did not show age-dependent mtDNA polymorphisms. In addition, the analysis of the restriction patterns of all the mtDNAs revealed 12 mtDNA haplotypes in all the Chinese subjects examined. Among them, type 1 mtDNA was found to be the most predominant and comprised 63.3% of the total study subjects. The restriction patterns of type 1 mtDNA generated by all restriction enzymes were identical to those deduced from the Cambridge sequence of human mtDNA. About 8.3% of the subjects exhibited type 2 mtDNA, and 5% had types 3, 5 and 8 mtDNA, respectively. Each of the rest seven mtDNA types comprised about 2% of the samples. Moreover, type 1 mtDNA was found in the platelets of three white Americans. These findings suggest that type 2 to type 12 mtDNAs have come into existence through the generation or loss of specific polymorphic restriction sites in the mtDNA of the Chinese.
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PMID:Specific restriction fragment length polymorphism in liver mitochondrial DNA of the Chinese. 135 20

The expression of both mitochondrial and nuclear genes encoding enzymes involved in electron transport and oxidative phosphorylation was examined in bovine cardiac tissue during early growth, development and aging. The steady state level of mRNAs for mitochondrial genes including ATPase 6. COXII and cyt b increased 2.5-4-fold relative to early fetal levels in late fetal and young adult tissues and showed a marked decline (30-50%) in older adult tissues. Similar results were found with the nuclear genes, COXVB and ATP-beta synthase showing coordinate regulation of the two genomes. An increase in mtDNA copy number correlated with the increase in transcript level. Enzyme activity levels for NADH dehydrogenase and cytochrome c oxidase showed a similar trend, albeit of lesser magnitude. These activity levels contrasted with the activity level of an entirely nuclear-encoded mitochondrial enzyme, citrate synthase, which increased not only throughout development but in the older adult tissue. This study indicates that there is a pattern of increasing mitochondrial and nuclear gene expression for OXPHOS enzymes in developing cardiac tissue and decreasing OXPHOS gene expression in the aging heart.
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PMID:Mitochondrial gene expression during bovine cardiac growth and development. 779 43

Infection with SIVmac251 in some rhesus monkeys (Macaca mulatta) leads to B-cell non-Hodgkin's lymphomas (B-NHL) clinically similar to that of HIV-infected AIDS patients. To further characterize the SIV-associated B-NHL we have generated genetic profiles of malignant cells by subtractive hybridization and Northern blot analysis. We have analyzed 21 clones of a subtracted cDNA library corresponding to overexpressed genes in diffuse large B-cell (DLBCL) SIV-associated monkey lymphoma. Eight of these clones represent a sequence homologous to an abundant transcript from KG-1 cells originally established from a human myelogenous leukemia. The protein encoded has a 60% similarity to a hypothetical glycine-rich transmembrane signal protein of Caenorhabditis elegans and 25% similarity to the ret finger protein. The other cDNA clones contained sequences of the serum amyloid A gene (SAA), the alpha1-acid glycoprotein gene (AGP), the ribosomal protein S3a (RPS3a) and L8 (RPL8) genes, the interferon-inducible gene (INF-ind), the metastasin gene (mts1), and the NADH dehydrogenase I gene (ND-I). The remaining cDNA clones consisted of yet unknown sequences. In addition, we detected an up-regulation of the cytochrome c oxidase II gene (COX-II), the ND-IV gene, and the SET oncogene by Northern blot hybridization in three SIV-associated NHLs of different histomorphological classification. All these genes have not previously been found to be overexpressed in B-NHL.
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PMID:Differential gene expression in B-cell non-Hodgkin's lymphoma of SIV-infected monkey. 1065 56

Type 2 diabetes has been related to a decrease of mitochondrial DNA (mtDNA) content. In this study, we show increased expression of the peroxisome proliferator-activated receptor-alpha (PPARalpha) and its target genes involved in fatty acid metabolism in skeletal muscle of Zucker Diabetic Fatty (ZDF) (fa/fa) rats. In contrast, the mRNA levels of genes involved in glucose transport and utilization (GLUT4 and phosphofructokinase) were decreased, whereas the expression of pyruvate dehydrogenase kinase 4 (PDK-4), which suppresses glucose oxidation, was increased. The shift from glucose to fatty acids as the source of energy in skeletal muscle of ZDF rats was accompanied by a reduction of subunit 1 of complex I (NADH dehydrogenase subunit 1, ND1) and subunit II of complex IV (cytochrome c oxidase II, COII), two genes of the electronic transport chain encoded by mtDNA. The transcript levels of PPARgamma Coactivator 1 (PGC-1) showed a significant reduction. Treatment with troglitazone (30 mg/kg/day) for 15 days reduced insulin values and reversed the increase in PDK-4 mRNA levels, suggesting improved insulin sensitivity. In addition, troglitazone treatment restored ND1 and PGC-1 expression in skeletal muscle. These results suggest that troglitazone may avoid mitochondrial metabolic derangement during the development of diabetes mellitus 2 in skeletal muscle.
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PMID:Impaired expression of NADH dehydrogenase subunit 1 and PPARgamma coactivator-1 in skeletal muscle of ZDF rats: restoration by troglitazone. 1456 25

All tumors examined to date contain mutations in mitochondrial DNA (mtDNA). In addition, depletion of mtDNA is reported in a variety of tumors. Mitochondrial dysfunction resulting from changes in mtDNA invokes mitochondria-to-nucleus retrograde response in human cells. To identify proteins involved in retrograde response and their potential role in tumorigenesis, we carried out a comparative proteomic analysis using a cell line in which the mitochondrial genome was completely depleted (rho(0) cells lacking all mtDNA-encoded protein subunits), a cybrid cell line in which mtDNA was restored, and the parental cell line. Our comparative proteomic approach revealed marked changes in the cellular proteome and led us to identify quantitative changes in expression of several proteins. We found that subunits of complex I and complex III, molecular chaperones, and a protein involved in cell cycle control were downregulated and Inosine 5'-monophosphate dehydrogenase type 2 (IMPDH2) involved in nucleotide biosynthesis was upregulated in rho(0) cells. Our findings demonstrate that the expression of proteins is restored to wild type level by transfer of wild type mitochondria to rho(0) cells, suggesting that these proteins play key roles in retrograde response. To determine a potential role for identified retrograde responsive proteins in tumorigenesis, we analyzed the expression of UQCRC1 gene (encoding ubiquinol cytochrome-c reductase core protein I) in breast and ovarian tumors. We found that (1) UQCRC1 was highly expressed in breast (74%) and ovarian tumors (34%) and (2) the expression positively correlated with cytochrome c-oxidase (COXII) encoded by mtDNA. Our study opens an avenue for identification of retrograde proteins as potential tumor suppressors or oncogenes involved in carcinogenesis.
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PMID:Proteomic analysis of mitochondria-to-nucleus retrograde response in human cancer. 1696 84

This study investigated the genetic and enzymological features of Leigh syndrome due to respiratory chain complex deficiency in Chinese patients. The clinical features of 75 patients were recorded. Mitochondrial respiratory chain enzyme activities were determined via spectrophotometry. Mitochondrial gene sequence analysis was performed in 23 patients. Five core pedigrees were investigated via restriction fragment length polymorphism and gene sequencing. Psychomotor retardation (55%), motor regression (20%), weakness (29%), and epilepsy (25%) were the most frequent manifestations. Sixty-four patients (85.3%) had isolated respiratory complex deficiencies: complex I was seen in 28 patients (37.3%); complex II, seven (9.3%); complex III, six (8%); complex IV, ten (13.3%); and complex V, 13 patients (17.3%). Eleven patients (14.7%) had combined complex deficiencies. Mitochondrial DNA mutations were detected in 10 patients. Eight point mutations were found in mitochondrial structural genes: m.4833A>G in ND2, m.10191T>C in ND3, m.12338T>C and m.13513G>A in ND5, m.14502T>C and m.14487T>C in ND6, m.8108A>G in COXII, and m.8993T>G in ATPase6. Three mutations were found in tRNA genes: m.4395A>G in tRNA-Gln, m.10454T>C in tRNA-Arg, and m.5587T>C in tRNA-Ala. One patient and their mother both had the m.12338T>C and m.8993T>C mutations. In conclusion, mitochondrial respiratory chain complex I deficiency and structural gene mutations frequently occur in Chinese Leigh syndrome patients.
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PMID:Genetic and biochemical findings in Chinese children with Leigh syndrome. 2395 30

Novel, single-nucleotide mutations were identified in the mitochondrial methionyl amino-acyl tRNA synthetase gene (MARS2) via whole exome sequencing in two affected siblings with developmental delay, poor growth, and sensorineural hearing loss.We show that compound heterozygous mutations c.550C>T:p.Gln 184* and c.424C>T:p.Arg142Trp in MARS2 lead to decreased MARS2 protein levels in patient lymphoblasts. Analysis of respiratory complex enzyme activities in patient fibroblasts revealed decreased complex I and IV activities. Immunoblotting of patient fibroblast and lymphoblast samples revealed reduced protein levels of NDUFB8 and COXII, representing complex I and IV, respectively. Additionally, overexpression of wild-type MARS2 in patient fibroblasts increased NDUFB8 and COXII protein levels. These findings suggest that recessive single-nucleotide mutations in MARS2 are causative for a new mitochondrial translation deficiency disorder with a primary phenotype including developmental delay and hypotonia. Identification of additional patients with single-nucleotide mutations in MARS2 is necessary to determine if pectus carinatum is also a consistent feature of this syndrome.
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PMID:Novel, compound heterozygous, single-nucleotide variants in MARS2 associated with developmental delay, poor growth, and sensorineural hearing loss. 2575 15