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Grimm C, Kohli J. Observations on integrative transformation in Schizosaccharomyces pombe. MOLECULAR & GENERAL GENETICS : MGG 1988; 215:87-93. [PMID: 3241625 DOI: 10.1007/bf00331308] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Three different Schizosaccharomyces pombe strains have been transformed with a circular or linearized non-ars plasmid carrying the ura4+ gene as a selectable marker. The first strain shows full homology between the genomic ura4-294 gene (point mutation) and the marker gene on the plasmid. The second strain carries a 600 bp deletion (ura4-D6) that decreases homology between plasmid and chromosome. No homology remains in the third strain which has a complete deletion of the ura4 gene on the chromosome (ura4-D18). When sequence homology exists between transforming DNA and the chromosomal ura4 region, gene conversion is strongly preferred over integration of the circular plasmid. Reduction of the length of homology leads to a decrease of transformation frequencies, and homology dependent as well as a minority of homology independent integrations are observed. In the complete absence of homology two rare types of transformants are encountered: either the circular plasmid replicates autonomously, although it is devoid of an ars sequence, or alternatively the plasmid integrates into the genome at various positions. Transformation with plasmid cut within the coding region of ura4 can lead to tandemly arranged multiple integrations, when no homology exists between the free ends and the chromosome. The integrations occur at the ura4 locus, when homology is retained between plasmid and chromosome, and at various sites in the genome of the strain with a complete deletion of the ura4 gene. The results suggest that homology dependent events (conversion, integration) are strongly preferred in transformation of S. pombe with non-ars plasmids. In addition low frequency integration by illegitimate recombination is observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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Schuchert P, Kohli J. The Ade6-M26 Mutation of Schizosaccharomyces Pombe Increases the Frequency of Crossing over. Genetics 1988; 119:507-15. [PMID: 17246436 PMCID: PMC1203436 DOI: 10.1093/genetics/119.3.507] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
The ade6-M26 mutation of Schizosaccharomyces pombe increases conversion frequency in comparison with the nearby mutation ade6-M375. In order to investigate the effect of ade6-M26 on crossover frequency, heteroallelic ade6 duplications were constructed by integration of plasmids carrying the marker gene ura4. One ade6 gene carries either of the mutations M26 or M375 while the other ade6 copy carries the L469 mutation in both duplications. The duplication with ade6-M26 yields Ade(+) recombinants at significantly higher frequencies in meiosis, but not in mitosis. Tetrad analysis and physical characterization of spore clones from recombination tetrads demonstrate that conversions, unequal crossovers and intrachromatid exchanges occur at higher frequencies but with unaltered proportions among them. The conversion events show a pronounced bias when M26 is involved: they take place preferentially at the M26 allele. Thus the ade6-M26 mutation not only enhances conversion frequency as demonstrated before, but also crossover frequency. It displays the properties expected for a preferred site of initiation of general meiotic recombination. The duplications also yielded new information on ectopic recombination in S. pombe: ectopic crossovers occur in the duplications at much higher frequency than among naturally dispersed homologous sequences.
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Abstract
The nomenclature rules for the genetics of the fission yeast Schizosaccharomyces pombe have been fixed for the first time, after discussion among scientists working with this organism. Conventions are proposed for the naming of genes and alleles that are obtained by classical means or by reverse genetics. In addition a list has been compiled of 460 known genes of S. pombe. It includes genes defined both by classical mutation analysis and by molecular cloning. 270 genes have been assigned either to one of the three nuclear chromosomes or the mitochondrial genome.
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Kohli J, Bhattacharya SK, Gupta VS, Sen P, Chakravarty AK. Effect of metronidazole on immune mechanism in experimental animals. INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY 1987; 25:177-80. [PMID: 3666815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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55
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Grossenbacher AM, Stadelmann B, Heyer WD, Thuriaux P, Kohli J, Smith C, Agris PF, Kuo KC, Gehrke C. Antisuppressor mutations and sulfur-carrying nucleosides in transfer RNAs of Schizosaccharomyces pombe. J Biol Chem 1986; 261:16351-5. [PMID: 3782124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Antisuppressor mutations reduce the efficiency of nonsense suppressors. A mutation in the gene sin4 of Schizosaccharomyces pombe leads to loss of 5-(methoxycarbonylmethyl) thiouridine (mcm5s2U) from the first anticodon position of tRNAs. This resembles the phenotype of sin3 (Heyer, W. D., Thuriaux, P., Kohli, J., Ebert, P., Kersten, H., Gehrke, C., Kuo, K. C., and Agris, P. F. (1984) J. Biol. Chem. 259, 2856-2862), but the mutations reside in different genes. In vivo 35S-labeled tRNA from the parental suppressor strain sup3, the antisuppressor strains sin3 and sin4, and the double mutant sin3 sin4 has been digested to nucleosides and analyzed with high performance liquid chromatography methods. The major sulfur-carrying nucleoside in wild-type S. pombe tRNA is mcm5s2U. It is reduced in the mutant strains. Two other thiolated nucleosides are also present: 2-thiouridine and a nucleoside of unknown structure. Neither was affected by the antisuppressor mutations. Thiocytidine has not been found. Independent from their effect on suppressors, the two mutations sin3 and sin4 reduce the growth rate of cells, and sin3 also increases cell length. In vivo decoding of the serine codon UCG by the UCA reading serine tRNA is not promoted by the two antisuppressor mutations.
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Willis I, Nichols M, Chisholm V, Söll D, Heyer WD, Szankasi P, Amstutz H, Munz P, Kohli J. Functional complementation between mutations in a yeast suppressor tRNA gene reveals potential for evolution of tRNA sequences. Proc Natl Acad Sci U S A 1986; 83:7860-4. [PMID: 3532123 PMCID: PMC386822 DOI: 10.1073/pnas.83.20.7860] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Successive rounds of mutagenesis of a Schizosaccharomyces pombe strain bearing the UGA-reading sup3 tRNASer suppressor have been carried out for two cycles of inactivation and reactivation of the suppressor. The suppressor phenotype at each stage was found to involve different combinations of three mutations, A30, A53, and A67, in the sup3-UGA gene. Single mutations A30 and A53 inactivate the suppressor as does the presence of all three mutations. A67 by itself is phenotypically neutral, but in combination with either A30 or A53 suppressor function is restored. The frequency with which these and other complementation events occur in S. pombe demonstrates a significant potential for nucleotide sequence evolution in tRNA. Differential expression of the S. pombe genes in Saccharomyces cerevisiae suggests that the two yeasts have diverged at the transcriptional and RNA processing level. Processing of the mutant tRNA precursors in S. cerevisiae reveals a hierarchy of structural domains within the tRNA that vary in their importance for RNase P cleavage.
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Heyer WD, Munz P, Amstutz H, Aebi R, Gysler C, Schuchert P, Szankasi P, Leupold U, Kohli J, Gamulin V. Inactivation of nonsense suppressor transfer RNA genes in Schizosaccharomyces pombe. Intergenic conversion and hot spots of mutation. J Mol Biol 1986; 188:343-53. [PMID: 3735426 DOI: 10.1016/0022-2836(86)90159-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Intergenic conversion is a mechanism for the concerted evolution of repeated DNA sequences. A new approach for the isolation of intergenic convertants of serine tRNA genes in the yeast Schizosaccharomyces pombe is described. Contrary to a previous scheme, the intergenic conversion events studied in this case need not result in functional tRNA genes. The procedure utilizes crosses of strains that are homozygous for an active UGA suppressor tRNA gene, and the resulting progeny spores are screened for loss of suppressor activity. In this way, intergenic convertants of a tRNA gene are identified that inherit varying stretches of DNA sequence from either of two other tRNA genes. The information transferred between genes includes anticodon and intron sequences. Two of the three tRNA genes involved in these information transfers are located on different chromosomes. The results indicate that intergenic conversion is a conservative process. No infidelity is observed in the nucleotide sequence transfers. This provides further evidence for the hypothesis that intergenic conversion and allelic conversion are the result of the same molecular mechanism. The screening procedure for intergenic revertants also yields spontaneous mutations that inactivate the suppressor tRNA gene. Point mutations and insertions of A occur at various sites at low frequency. In contrast, A insertions at one specific site occur with high frequency in each of the three tRNA genes. This new type of mutation hot spot is found also in vegetative cells.
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Heyer WD, Sipiczki M, Kohli J. Replicating plasmids in Schizosaccharomyces pombe: improvement of symmetric segregation by a new genetic element. Mol Cell Biol 1986; 6:80-9. [PMID: 3023839 PMCID: PMC367486 DOI: 10.1128/mcb.6.1.80-89.1986] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We characterized a number of widely used yeast-Escherichia coli shuttle vectors in the fission yeast Schizosaccharomyces pombe. The 2 micron vectors pDB248 and YEp13 showed high frequency of transformation, intermediate mitotic and low meiotic stability, and a low copy number in S. pombe, analogous to their behavior in [cir0] strains of Saccharomyces cerevisiae. The S. cerevisiae integration vectors pLEU2 and pURA3 transformed S. pombe at very low frequencies but, surprisingly, in a nonintegrative fashion. Instead, they replicated autonomously, and they showed very high copy numbers (up to 150 copies per plasmid-containing cell). This could reflect a lack of sequence specificity for replication of plasmid DNA in S. pombe. pFL20, an S. pombe ars vector, and a series of plasmids derived from it were studied to analyze the unusually high stability of this plasmid. Mitotic stability and partitioning of the plasmids was measured by pedigree analysis of transformed S. pombe cells. An S. pombe DNA fragment (stb) was identified that stabilizes pFL20 by improvement of plasmid partitioning in mitosis and meiosis.
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Amstutz H, Munz P, Heyer WD, Leupoid U, Kohli J. Concerted evolution of tRNA genes: intergenic conversion among three unlinked serine tRNA genes in S. pombe. Cell 1985; 40:879-86. [PMID: 3921260 DOI: 10.1016/0092-8674(85)90347-2] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In many cases the multiple genes coding for one specific tRNA are dispersed throughout the genome. The members of such a gene family nevertheless maintain a common nucleotide sequence during evolution. A major mechanism contributing to this concerted evolution is intergenic conversion. Here we show that it occurs between three tRNA genes of related sequence residing on different chromosomes of Schizosaccharomyces pombe. Sequence analysis of converted genes indicates that blocks of a minimal length of 18-33 bp and of a maximal length of 190 bp can be transferred from one gene to the other. During meiosis the frequency of these transfers lies in the order of 10(-5) per progeny spore. Information transfer between any two members of the gene family occurs in both directions.
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60
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Heyer WD, Thuriaux P, Kohli J, Ebert P, Kersten H, Gehrke C, Kuo KC, Agris PF. An antisuppressor mutation of Schizosaccharomyces pombe affects the post-transcriptional modification of the "wobble" base in the anticodon of tRNAs. J Biol Chem 1984; 259:2856-62. [PMID: 6559822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
The screening of antisuppressor mutants of the yeast Schizosaccharomyces pombe has been successfully accomplished with high resolution liquid chromatographic methods for the analysis of tRNA nucleosides. Antisuppressor mutations reduce or abolish the function of nonsense suppressor-tRNAs or other informational suppressors. Nonradioactive or 35S-labeled unfractionated tRNA from various strains was digested to nucleosides and analyzed by high performance liquid chromatography. The mutant sin3 has lost the nucleoside 5-(methoxycarbonylmethyl)-2-thiouridine from its tRNA in comparison to parental strains. In eukaryotes this nucleoside is found at the first position of the anticodon (wobble position) in several isoacceptor tRNAs that preferentially recognize codons ending with adenosine. The sin3 mutation reduces the efficiency of UGA and UAA suppressor tRNASer and suppressor tRNALeu. The genetic cosegregation of modification loss, antisuppressor phenotype, and a change in cell size is demonstrated. This indicates that a single mutation in the structural gene for a tRNA modification enzyme causes the three different phenotypes.
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61
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Hottinger H, Stadelmann B, Pearson D, Frendewey D, Kohli J, Söll D. The Schizosaccharomyces pombe sup3-i suppressor recognizes ochre, but not amber codons in vitro and in vivo. EMBO J 1984; 3:423-8. [PMID: 6370683 PMCID: PMC557361 DOI: 10.1002/j.1460-2075.1984.tb01823.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inefficient suppressor sup3-i of the fission yeast Schizosaccharomyces pombe is an ochre suppressor. Sup3-i was derived from the efficient serine inserting UGA suppressor sup3-e. The cloning and sequencing of the sup3-i gene indicate that the suppressor is different from the parent sup3-e by a C----T substitution in the sequence coding for the middle position of the anticodon. In vitro translation assays supplemented with purified sup3-i tRNA and programmed with Xenopus globin mRNAs lead to the accumulation of a readthrough product in response to UAA termination signals, but not in response to UGA termination codons. Transformation of Saccharomyces cerevisiae nonsense mutant strains with plasmid DNA carrying the S. pombe sup3-i gene, led to ochre, but not amber or UGA suppression in vivo.
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62
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Kohli J, Munz P, Aebi R, Amstutz H, Gysler C, Heyer WD, Lehmann L, Schuchert P, Szankasi P, Thuriaux P. Interallelic and intergenic conversion in three serine tRNA genes of Schizosaccharomyces pombe. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1984; 49:31-40. [PMID: 6597758 DOI: 10.1101/sqb.1984.049.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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63
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Munz P, Amstutz H, Kohli J, Leupold U. Recombination between dispersed serine tRNA genes in Schizosaccharomyces pombe. Nature 1982; 300:225-31. [PMID: 6924071 DOI: 10.1038/300225a0] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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64
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Kohli J, Sharma KK, Bapna JS, Sen P. Monoaminergic mechanisms in pilocarpine induced analgesia in mice. Indian J Med Res 1982; 76:342-7. [PMID: 7174026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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65
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Munz P, Leupold U, Agris P, Kohli J. In vivo decoding rules in Schizosaccharomyces pombe are at variance with in vitro data. Nature 1981; 294:187-8. [PMID: 7300901 DOI: 10.1038/294187a0] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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66
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Bienz M, Kubli E, Kohli J, deHenau S, Huez G, Marbaix G, Grosjean H. Usage of the three termination codons in a single eukaryotic cell, the Xenopus laevis oocyte. Nucleic Acids Res 1981; 9:3835-50. [PMID: 7024919 PMCID: PMC327395 DOI: 10.1093/nar/9.15.3835] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Oocytes from Xenopus laevis were injected with purified amber (UAG), ochre (UAA), and opal (UGA) suppressor tRNAs from yeasts. The radioactively labeled proteins translated from the endogenous mRNAs were then separated on two-dimensional gels. All three termination codons are used in a single cell, the Xenopus laevis oocyte. But a surprisingly low number of readthrough polypeptides were observed from the 600 mRNAs studied in comparison to uninjected oocytes. The experimental data are compared with the conclusions obtained from the compilation of all available termination sequences on eukaryotic and prokaryotic mRNAs. This comparison indicates that the apparent resistance of natural termination codons against readthrough, as observed by the microinjection experiments, cannot be explained by tandem or very close second stop codons. Instead it suggests that specific context sequences around the termination codons may play a role in the efficiency of translation termination.
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67
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Kohli J, Grosjean H. Usage of the three termination codons: compilation and analysis of the known eukaryotic and prokaryotic translation termination sequences. MOLECULAR & GENERAL GENETICS : MGG 1981; 182:430-9. [PMID: 6946272 DOI: 10.1007/bf00293932] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The published translation termination sequences have been compiled and analysed to aid the interpretation of experiments on termination codon usage in the Xenopus oocyte (Bienz et al. 1981). There are significant differences between prokaryotes and eukaryotes concerning the usage of the three termination codons and of tandem stops. In addition viruses show termination strategies that differ from those of their hosts. Preferred context sequences flanking termination codons are described. Contexts vary within the last codon according to the nature of the termination codon, but are uniform within the first triplet following the terminators.
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68
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69
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Bienz M, Kubli E, Kohli J, de Henau S, Grosjean H. Nonsense suppression in eukaryotes: the use of the Xenopus oocyte as an in vivo assay system. Nucleic Acids Res 1980; 8:5169-78. [PMID: 7465411 PMCID: PMC324292 DOI: 10.1093/nar/8.22.5169] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Amber, ochre, and opal nonsense suppressor tRNAs isolated from yeast were injected into Xenopus laevis oocytes together with purified mRNAs (globin mRNA from rabbit, tobacco mosaic virus-RNA). Yeast opal suppressor tRNA is able to read the UGA stop codon of the rabbit beta-globin mRNA, thus producing a readthrough protein. A large readthrough product is also obtained upon coinjection of yeast amber or ochre suppressor tRNA with TMV-RNA. The amount of readthrough product is dependent on the amount of injected suppressor tRNA. The suppression of the terminator codon of TMV-RNA is not susceptible to Mg++ concentration or polyamine addition. Therefore, the Xenopus laevis oocyte provides a simple, sensitive, and well buffered in vivo screening system for all three types of eukaryotic nonsense suppressor tRNAs.
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70
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De Ronde A, Van Loon AP, Grivell LA, Kohli J. In vitro suppression of UGA codons in a mitochondrial mRNA. Nature 1980; 287:361-3. [PMID: 6252475 DOI: 10.1038/287361a0] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Although both prokaryotic and eukaryotic messenger RNAs can be easily translated in heterologous protein-synthesizing systems, attempts to achieve correct synthesis of mitochondrial proteins by translation of mitochondrial mRNAs in such systems have failed. In general, the products of synthesis are of low molecular weight and presumably represent fragments of mitochondrial proteins. These fragments display a strong tendency to aggregate. Explanations have included the use by mitochondria of codons requiring a specialized tRNA population and the fortuitous occurrence within genes of purine-rich sequences resembling bacterial ribosome binding sites. In addition, the long 5'-leader sequences present in many mitochondrial (mt) RNAs may also contribute to difficulties in mRNA recognition by heterologous ribosomes. Recent sequence analysis of human mtDNA suggests that the genetic code used by mammalian mitochondria deviates in a number of respects from the 'universal' code, the most striking of these being the use of the UGA termination codon to specify tryptophan. That this may also apply in yeast mitochondria has been shown by Fox and Macino et al., thus providing an obvious and easily testable explanation for the inability of heterologous systems to synthesize full-length mitochondrial proteins. We confirm this explanation and describe here the in vitro synthesis of a full-length subunit II of yeast cytochrome c oxidase in a wheat-germ extract supplemented with a partially purified mitochondrial mRNA for this protein and a UGA-suppressor tRNA from Schizosaccharomyces pombe.
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71
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Abstract
1. The metabolism of several halogenated biphenyls has been studied using poultry as a model system. The substrates 4-chlorobiphenyl and 4-bromobiphenyl each yielded two metabolites (4'-chloro-4-biphenylol, 4'-chloro-3,4-biphenyldiol; 4'-bromo-4-biphenylol, 4'-bromo-3,4-biphenyldiol), while 4,4'-dichlorobiphenyl yielded only one metabolite (4,4-dichloro-3-biphenylol). 2. Metabolites were not found in eggs collected for 7 days following the administration of the substrate.
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72
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Rafalski A, Kohli J, Agris P, Söll D. The nucleotide sequence of a UGA suppressor serine tRNA from Schizosaccharomyces pombe. Nucleic Acids Res 1979; 6:2683-95. [PMID: 461200 PMCID: PMC327885 DOI: 10.1093/nar/6.8.2683] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The UGA suppressor tRNA produced by Schizosaccharomyces pombe strain sup3-e was purified to homogeneity. It can be aminoacylated with a serine by a crude aminoacyl-tRNA synthetase preparation from S. pombe cells. By combining post-labeling fingerprinting and gel sequencing methods the nucleotide sequence of this tRNA was determined to be: pG-U-C-A-C-U-A-U-G-U-C-ac4C-G-A-G-D-G-G-D-D-A-A-G-G-A-m2G2-psi-U-A-G-A-N-U-U-C-A-i6A-A-psi-C-U-A-A-U-G-G-G-C-U-U-U-G-C-C-C-G-m5C-G-G-C-A-G-G-T-psi-C-A-m1A-A-U-C-C-U-G-C-U-G-G-U-G-A-C-G-C-C-A OH. The anticodon sequence u ca is complementary to the UGA codon.
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73
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Wetzel R, Kohli J, Altruda F, Söll D. Identification and nucleotide sequence of the sup8-e UGA-suppressor leucine tRNA from Schizosaccharomyces pombe. MOLECULAR & GENERAL GENETICS : MGG 1979; 172:221-8. [PMID: 289895 DOI: 10.1007/bf00268286] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Using the translation of rabbit globin mRNA in wheat germ extracts as an assay for ochre and opal suppression, a UGA suppressor tRNA from Schizosaccharomyces pombre strain sup8-e was purified by column chromatography and two-dimensional gel electrophoresis. The purified tRNA can be aminoacylated with leucine by a crude aminoacyl-tRNA synthetase preparation from a wild type S. pombe strain, and has high activity in the suppressor assay. By a combination of post-labeling fingerprinting and rapid gel sequencing methods the nucleotide sequence of this suppressor tRNA was determined to be: pG-C-G-G-C-U-A-U-G-C-C-ac4C-G-A-G-D-G-G-D-G-D-A-A-G-G-G-m22G-G-C-A-G-A-psi-U-U*-C-A-m1G-C-C-C-U-G-C-U-G-U-U-G-U-A-A-A-A-C-G-m5C-G-A-G-A-G-T-psi-C-G-m1A-A-C-C-U-C-U-C-U-G-G-C-C-G-C-A-C-C-AOH. The anticodon sequence U*CA is complementary to the UGA codon. An interesting feature of the suppressor tRNA is an expanded anticodon loop of nine nucleotides owing to an A-C nonpair at the first anticodon stem position.
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74
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Kohli J, Kwong T, Altruda F, Söll D, Wahl G. Characterization of a UGA-suppressing serine tRNA from Schizosaccharomyces pombe with the help of a new in vitro assay system for eukaryotic suppressor tRNAs. J Biol Chem 1979; 254:1546-51. [PMID: 762155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Two different allele-specific suppressor mutants of the fission yeast Schizosaccharomyces pombe produce opal (UGA) suppressor tRNAs. This was shown by the use of a new in vitro assay for eukaryotic nonsense suppression: a wheat germ extract is programmed with rabbit globin mRNAs and the readthrough products are studied. alpha-Globin is elongated upon addition of ochre (UAA) suppressor tRNAs, whereas beta-globin yields a readthrough product with opal suppressor tRNAs. This simple and very sensitive assay allowed the purification of the opal suppressor tRNA from S. pombe strain sup3-e. The pure tRNA can be aminoacylated with serine; thus, we conclude that this suppressor tRNA inserts serine in response to the UGA termination codon of pure rabbit beta-globin mRNA.
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75
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Wong TW, McCutchan T, Kohli J, Söll D. The nucleotide sequence of the major glutamate transfer RNA from Schizosaccharomyces pombe. Nucleic Acids Res 1979; 6:2057-68. [PMID: 379816 PMCID: PMC327836 DOI: 10.1093/nar/6.6.2057] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The nucleotide sequence of glutamate tRNA1 from Schizosaccharomyces pombe was determined to be pU-C-C-G-U-U-G-U-m1G-G-U-C-C-A-A-C-G-G-C-D-A-G-G-A-U-U-C-G-U-C-G-C-U-U-U*-C-A-C-C-G-A-C-G-G-G-A-G-m5C-G-G-G-G-T-psi-C-G-A-C-U-C-C-C-C-G-C-A-A-C-G-G-A-G-C-C-AOH. The sequence differs markedly from that of S. cerevisiae tRNAGlu. S. pombe glutamate tRNA1 can be aminoacylated by the homologous glutaminyl-tRNA synthetase as well as by the corresponding enzyme from S. cerevisiae.
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