A pathway of cytochrome b mRNA processing in yeast mitochondria: Specific splicing steps and an intron-derived circular RNA

Halbreich, A.; Pajot, Patrick; Foucher, M.; Grandchamp, Claude; Słonimski, Piotr P.

doi:10.1016/0092-8674(80)90506-1

Cited by 124 publications

(45 citation statements)

References 14 publications

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“…The observation that mutants in box3 also exhibit the BOX phenotype is probably due to their inability to generate the trans-acting "box7+ product". Their reported (15,16,17,25) fiailure to process the box7 intron normally is consistent with this supposition. The converse does not appear to hold: box7 mutants experience no difficulty in processing the first (box3) intron.…”

Section: Discussionsupporting

confidence: 75%

“…These inferences are equally compatible with either of the models currently favored to account for intron function-i.e., specification of RNA guides or of a maturase protein (1,3,7,15,16 The first of these contained a Mr 20,000 fragment (Fig. 3C) that, upon digestion with a second protease, yielded identical peptides unrelated to cytochrome b and therefore probably orginated from intron sequences (26).…”

Section: Discussionmentioning

confidence: 99%

“…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 restricted to certain mutants in exon cluster box5/4 (3,7,(9)(10)(11)(12)(13)(14)(15)22).…”

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.…”

mentioning

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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Section: Discussionsupporting

confidence: 75%