Analysis of a DNA segment from rat liver mitochondria containing the genes for the cytochrome oxidase subunits I, II and III, ATPase subunit 6, and several tRNA genes

Grosskopf, Rüdiger; Feldmann, Horst

doi:10.1007/bf00365694

Cited by 73 publications

(15 citation statements)

References 32 publications

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“…Sequencing and comparison to data in Genbank [28] revealed that they were homologous to the gene-encoding subunit II of rat mitochondrial cytochrome C oxidase [6]. One clone (El) of 606 bp was used in additional investigations, because it almost completely covered the mature COX II mRNA (aligned to bases 2141-2747), encoded by bases 2117-2800 of the mitochondrial H strand [7,29].…”

Section: Isolation Of Cox II Clonesmentioning

confidence: 99%

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Mitochondrial Cytochrome C Oxidase II Messenger Ribonucleic Acid is Expressed in Pachytene Spermatocytes at High Levels and in a Stage-Dependent Manner during Spermatogenesis in the Rat

Saunders

Millar

West

et al. 1993

Biology of Reproduction

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Screening of a rat seminiferous tubule library (stages VI-VIII) resulted in isolation of several clones to the same abundant mRNA. Sequencing revealed that these encoded all or part of the second subunit of cytochrome C oxidase (COX II), the terminal enzyme in the electron transport chain located in mitochondria. The pattern of expression of the COX II mRNA in the testis was examined by Northern blot and in situ hybridisation combined with specific depletion of pachytene spermatocytes or Leydig cells by treatment with methoxyacetic acid (MAA) or ethane dimethane sulphonate (EDS), respectively. COX II mRNA was found to be strongly expressed in pachytene spermatocytes in adult and prepubertal rats, with the highest levels of expression at stages VII-VIII of the spermatogenic cycle. Although this is the androgen-dependent stage, Northern analysis of total testicular RNA showed that expression of COX II mRNA was not altered detectably by EDS-induced androgen withdrawal nor was expression altered detectably by 24-h treatment with high doses of FSH. Treatment of rats with MAA, which selectively depletes seminiferous tubules at most stages of pachytene spermatocytes, resulted in a marked reduction in COX II mRNA. In the absence of pachytene spermatocytes, COX II mRNA was visualized in preleptotene spermatocytes and in Sertoli cell cytoplasm. The expression of COX II in Sertoli cells was confirmed by examination in situ of a testis devoid of most germ cells and by Northern analysis of RNA from an adult Sertoli cell-enriched preparation. However, using either approach the amount of mRNA in Sertoli cells was considerably lower than that in pachytene spermatocytes. Cytochrome C oxidase has thirteen subunits, three of which (I-III) are encoded on the mitochondrial genome. The physiological significance of the high levels of expression of COX II mRNA in pachytene spermatocytes and its stage-dependent changes is unknown but they presumably reflect requirements for alterations in energy demand as these cells enter the final stages of meiosis. The stage-dependent differences in expression of COX II mRNA in pachytene spermatocytes may also explain differences in the susceptibility of these cells to depletion by MAA.

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Section: Isolation Of Cox II Clonesmentioning

confidence: 99%

“…Sequencing revealed that the cDNAs encoded all or part of the gene for cytochrome oxidase II (COX II) [6,7]. Cytochrome oxidase is the terminal enzyme in the electron transport chain located on the inner membrane of mitochondria, and it functions to generate adenosine triphosphate (ATP) required for cellular processes [8].…”

Section: Introductionmentioning

confidence: 99%

Mitochondrial Cytochrome C Oxidase II Messenger Ribonucleic Acid is Expressed in Pachytene Spermatocytes at High Levels and in a Stage-Dependent Manner during Spermatogenesis in the Rat

Saunders

Millar

West

et al. 1993

Biology of Reproduction

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“…Its sequence (784bp) was 99.8% identical to the sequence of the mitochondrial gene [13]. The cDNA for rat COX subunit VIc, spanning part of the coding and the 3 noncoding region, cloned into the PstI site of pBluescribe, was described previously [14].…”

Section: Cdna Probes Hybridization Conditions and Detectionmentioning

confidence: 99%

Correlations between a nuclear and a mitochondrial mRNA of cytochrome c oxidase subunits, enzymatic activity and total mRNA content, in rat tissues

et al. 1991

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Cytochrome c oxidase (COX), like other multi-subunit components of the respiratory chain, is controlled by both the nuclear and the mitochondrial genome. In order to find wether there is a close relationship between mRNAs encoded by the nucleus and by the mitochondrion, and between these mRNAs and enzyme activity, we compared six rat tissues (ventricle, liver, m. soleus, m. plantaris, and the white and red portions of m. gastrocnemius). We found a tenfold range for COX activity, a tenfold range for the contents of mRNA III (mitochondrial) and mRNA VIc (nuclear), a threefold range for total [poly(A)+] mRNA content and a sevenfold range for total RNA content in these tissues. The ratio of mRNA III to mRNA VIc was equal in each tissue, indicating the presence of a mechanism that coordinates the two genomes. There was a good correlation between mRNA content and COX activity (r = 0.78 for VIc, r = 0.77 for III; p less than 0.0001), demonstrating that the expression of this enzyme is mainly under pretranslational control.

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“…(ii) The other clone, pSG 16, contained sequences coding for subunit I of the mitochondrial cytochrome oxydase (18); this gene is located in the mitochondrial rather than the nuclear genome. An increase in its expression has been previously associated with colony senescence in the unicellular mold Podospora anserina (22,44).…”

Section: Resultsmentioning

confidence: 99%

T-kininogen gene expression is induced during aging.

Sierra¹,

Fey²,

Guigoz³

1989

Mol. Cell. Biol.

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We have constructed a cDNA library from senescent (24-month-old) rat liver mRNA and, by differential screening, have selected clones corresponding to mRNA species with increased abundance in aging rats. Direct sequencing of the inserts indicated that most of the clones (9 of 10) contained sequences coding for T-kininogen, also called major acute-phase protein, cysteine protease inhibitor, or thiostatin. Nuclear elongation experiments showed that the increase in mRNA concentration was controlled at the transcriptional level. RNase mapping and Si analysis indicated that the age-dependent induction operated preferentially at one of the three transcriptional start sites of the gene(s). The acute-phase reaction (inflammation) is known to also induce these genes at the level of transcription; however, two of the three start sites are induced by inflammation. Transcription from one of these sites was induced by both phenomena, aging and inflammation.During the past few years, major efforts have been made to understand developmental processes at the molecular level. Although many researchers have directed their efforts toward an understanding of the changes in gene expression that accompany early development, surprisingly little is known about the molecular changes that occur as the ultimate result of development, namely, senescence.We are particularly interested in the process of aging as well as the factors that might be able to affect this process. The phenomenon of aging is the result of an interplay of various components, both extrinsic (such as nutritional status or physical exercise) and intrinsic. The intrinsic processes can in turn be subdivided into two distinct classes: random events, which are usually triggered by extrinsic events such as UV irradiation or free-radical formation, and programmed events, which are inherently associated with the developmental pathway of the species in question. These programmed events include, for example, the changes in gene expression associated with the loss of hormonal balance (32,34). We are directing our efforts toward an understanding of the programmed changes in gene expression and metabolism that are normally associated with the process of aging.It has been observed for some time that aging is accompanied by an overall deregulation of gene activity (10,29,30,45). At the same time, several investigators have reported changes in the transcriptional activity of specific genes in several organisms (14,34,35,41,46,47). In many cases, transcriptional activity is reduced during aging because of the dependence of some genes on hormonal control. One such example is the extinction of expression of the a2U-globulin gene in aging animals (34). In this case, it has been shown that the gene is turned off not only because of a diminishing level of several controlling hormones but also because the receptors for these hormones appear to diminish with age (33). In addition, a recent report has shown that in aging animals, the a2U-globulin genes are detached from the nuclear matrix (28)....

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Analysis of a DNA segment from rat liver mitochondria containing the genes for the cytochrome oxidase subunits I, II and III, ATPase subunit 6, and several tRNA genes

Cited by 73 publications

References 32 publications

Mitochondrial Cytochrome C Oxidase II Messenger Ribonucleic Acid is Expressed in Pachytene Spermatocytes at High Levels and in a Stage-Dependent Manner during Spermatogenesis in the Rat

Mitochondrial Cytochrome C Oxidase II Messenger Ribonucleic Acid is Expressed in Pachytene Spermatocytes at High Levels and in a Stage-Dependent Manner during Spermatogenesis in the Rat

Correlations between a nuclear and a mitochondrial mRNA of cytochrome c oxidase subunits, enzymatic activity and total mRNA content, in rat tissues

T-kininogen gene expression is induced during aging.

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