Sequence of introns and flanking exons in wild-type and box3 mutants of cytochrome b reveals an interlaced splicing protein coded by an intron

Lazowska, Jaga; Jacq, Claude; Słonimski, Piotr P.

doi:10.1016/0092-8674(80)90344-x

Cited by 472 publications

(195 citation statements)

References 25 publications

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“…It would be interesting to know whether the outloop in the mt tRNAPh' and tRNAiyS also confers unusual decoding properties. An argument in favor of a possible frameshift suppressor function for these two tRNAs is provided by the existence of frameshift mutations which are leaky in yeast mitochondrial protein coding genes and which affect a UUU codon for phenylalanine [26] and an AAA codon for lysine [27]. The leakiness of the mutations could be due to the ability of the tRNAPhe and tRNAkYS to restore, at least to a certain extent, the correct reading frame.…”

Section: Structural Featuresmentioning

confidence: 99%

Codon reading patterns in Saccharomyces cerevisiae mitochondria based on sequences of mitochondrial tRNAs

1986

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The sequences of Saccharomyces cerevisiae mitochondrial tRNA1 Arg, tRNA2 Arg, tRNAGly, tRNA2 Lys tRNALeu and tRNAPro are reported. Special structural features were found in tRNAPro, which has A8, C21, A48 instead of the constant residues U8, A21 and pyrimidine 48, and in tRNA2 Lys, which has a U excluded from basepairing and bulging out from the TΨC stem. The tRNA1 Arg, tRNA2 Lys and tRNALeu, which belong to two‐codon families ending in a purine, have a modified uridine in the wobble position, which prevents misreading of C and U. It is likely to be 5‐carboxymethylaminomethyluridine. tRNAGly and tRNAPro have an unmodified uridine in the wobble position allowing the reading of all four codons of a four‐codon family. However, tRNA2 Arg, which is a minor species and belongs to the CGN four‐codon family, has an unmodified A in the wobble position. This very unusual feature raises the problem of the mechanism by which the codons CGA, CGG and CGC are recognized.

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Section: Structural Featuresmentioning

confidence: 99%

Codon reading patterns in Saccharomyces cerevisiae mitochondria based on sequences of mitochondrial tRNAs

1986

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“…The mutations were found to be of mitochondrial heredity and were located at two loci of the apocytochrome b gene. The diul locus was found to belong to exon 4 and the diu2 locus has been attributed to exon 1 of the long cytochrome b gene [3,4]. The cytochrome b gene carries other drug-resistant loci ( fig.…”

Section: Introductionmentioning

confidence: 99%

DNA sequence analysis of diuron‐resistant mutations in the mitochondrial cytochrome b gene of Saccharomyces cerevisiae

1986

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Diuron (3‐[34‐dichlorophenyl]‐1,1‐dimethylurea), an inhibitor of mitochondrial respiration blocks the yeast respiratory chain between cytochrome b and c 1. Diuron‐resistant mutants of Saccharomyces cerevisiae have been selected and several mutations localized to the mitochondrial cytochrome b gene. The present paper identifies specific DNA base changes within the cytochrome b gene conferring diuron‐resistance. DNA sequence analysis was done utilizing primer extension of crude mitochondrial RNA preparations in the presence of reverse transcriptase. Five independent diuron‐resistant mutations have been sequenced.

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“…1). Mutants in intervening sequences (introns) can also be readily obtained and have been mapped into three additional box loci: 3 (between 5/4 and 8), 10 (between 8 and 1/9), and 7 (between 1/9 and 2) (3,(9)(10)(11)(12). Second, whereas all exon mutants belong to a single complementation group, the three intron loci define three additional groups (3,9,13) that provide separate trans-acting elements required for proper expression of the wild-type gene, most likely involving maturation (splicing) of its initial transcript (3,7,(13)(14)(15)(16).…”

mentioning

confidence: 99%

“…Mutants in intervening sequences (introns) can also be readily obtained and have been mapped into three additional box loci: 3 (between 5/4 and 8), 10 (between 8 and 1/9), and 7 (between 1/9 and 2) (3,(9)(10)(11)(12). Second, whereas all exon mutants belong to a single complementation group, the three intron loci define three additional groups (3,9,13) that provide separate trans-acting elements required for proper expression of the wild-type gene, most likely involving maturation (splicing) of its initial transcript (3,7,(13)(14)(15)(16). A characteristic of intron mutations is the accumulation of RNA processing intermediates (7,12,(14)(15)(16)(17) and of novel hybrid proteins, translated from both the neighboring upstream exon(s) and from surviving downstream intron transcripts (6,12,(17)(18)(19)(20)(21).…”

mentioning

confidence: 99%

“…Second, whereas all exon mutants belong to a single complementation group, the three intron loci define three additional groups (3, 9, 13) that provide separate trans-acting elements required for proper expression of the wild-type gene, most likely involving maturation (splicing) of its initial transcript (3,7,(13)(14)(15)(16). A characteristic of intron mutations is the accumulation of RNA processing intermediates (7,12,(14)(15)(16)(17) and of novel hybrid proteins, translated from both the neighboring upstream exon(s) and from surviving downstream intron transcripts (6,12,(17)(18)(19)(20)(21). Third, mutations at a number of loci result in a pleiotropic (BOX) phenotype affecting not only the synthesis of cytochrome b but also that of subunit I of cytochrome oxidase (COX I), itself encoded in oxi3, a mosaic mitochondrial gene distant and upstream from cob (Fig.…”

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confidence: 99%

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Regulatory interactions between mitochondrial genes: interactions between two mosaic genes.

Dhawale¹,

Hanson²,

Alexander³

et al. 1981

Proc. Natl. Acad. Sci. U.S.A.

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We have studied the mitochondrial DNA and the phenotypes of strains of Saccharomyces cerevimiae with specific intervening sequences in two mosaic genes: cob (the gene for apocytochrome b) and oxi3 (the gene for subunit I of cytochrome oxidase). The results suggest the following. (i) The presence of an intervening sequence downstream encompassing the intron box7 is sufficient for the regulation of oxi3 by cob (BOX phenotype); two sequences (containing intron loci box3 and boxlO) upstream in cob and two in oxi3 are dispensable. (ii) Strains without the two sequences upstream still contain the downstream sequence and the competence to specify a functional trans-acting element. Mutational lesions in this segment are phenotypically indistinguishable from box7 mutants, including the accumulation of polypeptides with homologous amino acid sequences. (iii) A catabolite-sensitive BOX phenotype, characteristic of mutants in the first exon, requires the simultaneous presence of an adjacent intervening sequence. A model is presented in which a hypothetical product specified by an intron (locus box7) of the cob gene controls the expression of a second mosaic gene (oxi3). Recent studies on the organization and expression of the mitochondrial gene for apocytochrome b of the bc1 complex in Saccharomyces cerevisiae (cob gene) have revealed some remarkable properties (reviewed in refs. 1-3). First, the gene exhibits the mosaic organization characteristic of eukatyotic nuclear and viral genes, with sequences coding for protein (exons) interspersed among intervening sequences (4, 5). Mutants in exons have been mapped genetically and physically into five or more clusters referred to, in order of transcription and translation, as box loci 5/4, 8, 1/9, 2, and 6 ( Fig. 1). Mutants in intervening sequences (introns) can also be readily obtained and have been mapped into three additional box loci: 3 (between 5/4 and 8), 10 (between 8 and 1/9), and 7 (between 1/9 and 2) (3, 9-12). Second, whereas all exon mutants belong to a single complementation group, the three intron loci define three additional groups (3, 9, 13) that provide separate trans-acting elements required for proper expression of the wild-type gene, most likely involving maturation (splicing) of its initial transcript (3,7,(13)(14)(15)(16). A characteristic of intron mutations is the accumulation of RNA processing intermediates (7,12,(14)(15)(16)(17) and of novel hybrid proteins, translated from both the neighboring upstream exon(s) and from surviving downstream intron transcripts (6,12,(17)(18)(19)(20)(21). Third, mutations at a number of loci result in a pleiotropic (BOX) phenotype affecting not only the synthesis of cytochrome b but also that of subunit I of cytochrome oxidase (COX I), itself encoded in oxi3, a mosaic mitochondrial gene distant and upstream from cob (Fig. 1). This inhibition takes two forms: (i) stringent, manifested by most intron mutants examined, regardless of growth conditions, and (ii) conditional, dependent on catabolite repression and rest...

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Sequence of introns and flanking exons in wild-type and box3 mutants of cytochrome b reveals an interlaced splicing protein coded by an intron

Cited by 472 publications

References 25 publications

Codon reading patterns in Saccharomyces cerevisiae mitochondria based on sequences of mitochondrial tRNAs

Codon reading patterns in Saccharomyces cerevisiae mitochondria based on sequences of mitochondrial tRNAs

DNA sequence analysis of diuron‐resistant mutations in the mitochondrial cytochrome b gene of Saccharomyces cerevisiae

Regulatory interactions between mitochondrial genes: interactions between two mosaic genes.

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