Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four cytoplasmic mutants of Saccharomyces cerevisiae showing loss of mitochondrial rutamycin-sensitive ATPase activity but having significant cytochrome oxidase and NADH-cytochrome c reductase have been isolated. Genetic studies indicate the mutations to be closely linked to each other and have been assigned to a new locus, PHO1. The mutations show a low frequency of recombination with the OL12 locus, suggesting a linkage to this marker. They are not, however, linked to the OLI1 locus. Linkage of the ATPase mutations to the OLI2 locus is also indicated by restoration of wild-type diploids by sigma- clones that retain the segment of mitochondrial DNA carrying OLI2. Based on the recombinants issued from crosses of the mutants with a triple drug-resistant strain and an analysis of the resistance markers present in sigma- clones that are effective in restoring a wild-type phenotype, the PHO1 locus has been placed in the segment of DNA located between PAR1 and OLI2.
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PMID:Localization on mitochondrial DNA of mutations leading to a loss of rutamycin-sensitive adenosine triphosphatase. 13 92

1. Three methods are described for the genetic analysis of yeast cytoplasmic mutants (mit- mutants) lacking cytochrome oxidase or coenzyme QH2-cytochrome c reductase. The procedures permit mutations in mitochondrial DNA to be mapped relative to each other and with respect to drug-resistant markers. The first method is based upon the finding that crosses of mit- mutants with some but not other isonuclear q- mutants lead to the restoration of respiratory functions. Thus a segment of mitochondrial DNA corresponding to a given mit- mutation or to a set of mutations can be delineated. The second method is based on the appearance of wild-type progeny in mit- X mit- crosses. The third one is based on the analysis of various recombinant classes issued from crosses between mit-, drug-sensitive and mit+, drug-resistant mutants. Representative genetic markers of the RIBI, OLII, OLI2 and PAR1 loci were used for this purpose. 2. The three methods when applied to the study of 48 mit- mutants gave coherent results. At least three distinct regions on mitochondrial DNA in which mutations cause loss of functional cytochrome oxidase have been established. A fourth region represented by closely clustered mutants lacking coenzyme QH2-cytochrome c reductase and spectrally detectable cytochrome b has also been studied. 3. The three genetic regions of cytochrome oxidase and the cytochrome b region were localized by the third method on the circular map, in spans of mitochondrial DNA defined by the drug-resistant markers. The results obtained by this method were confirmed by analysis of the crosses between selected mit- mutants and a large number of q- clones whose retained segments of mitochondrial DNA contained various combinations of drug-resistant markers. 4. All the genetic data indicate that the various regions studied are dispersed on the mitochondrial genome and in some instances regions or clusters of closely linked mutations involved in the same respiratory function (cytochrome oxidase) are separated by other regions which code for entirely different functions such as ribosomal RNA.
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PMID:Localization in yeast mitochondrial DNA of mutations expressed in a deficiency of cytochrome oxidase and/or coenzyme QH2-cytochrome c reductase. 17 53