Construction of novel cytochrome b genes in yeast mitochondria by subtraction or addition of introns.
The mitochondrial cob-box gene coding for apocytochrome b in yeast has five introns and six exons or two introns and three exons depending on the wild-type strain considered. Some intron mutations in this gene affect not only its expression but also that of another mitochondrial gene: oxi3. To understand better the function of introns in gene expression, we have constructed a series of new strains that differ only by the presence or absence of one of the five wild-type introns in the cytochrome b gene, the rest of the mitochondrial and nuclear genome remaining unchanged. All constructions result from in vivo recombination events between rho- donor and rho+ recipient mtDNA. The following genes have been constructed: [see text]. Interestingly, all the genes lead to the synthesis of cytochrome b, while only the genes having the intron bI4 allow the expression of oxi3. A nuclear gene, when mutated, can compensate for the absence of the intron bI4.
Labouesse
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Centre de Génétique Moléculaire, Laboratoire propre du Centre National de la Recherche Scientifique associé à l'Université Pierre et Marie Curie, Gif-sur-Yvette, France.
Slonimski
P P
PP
D003573:Cytochrome b Group / Q000235:genetics*; D004272:DNA, Mitochondrial; D005800:Genes, Fungal; D005820:Genetic Testing; D007438:Introns; D008928:Mitochondria; D010641:Phenotype; D020161:Physical Chromosome Mapping; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics
D003573:Cytochrome b Group; D004272:DNA, Mitochondrial