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Cloning and expression of a cDNA copy of the viral K28 killer toxin gene in yeast

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Abstract

The killer toxin K28, secreted by certain killer strains of the yeast Saccharomyces cerevisiae is genetically encoded by a 1.9 kb double-stranded RNA, M-dsRNA (M28), that is present within the cell as a cytoplasmically inherited virus-like particle (VLP). For stable maintenance and replication, M28-VLPs depend on a second dsRNA virus (LA), which has been shown to encode the major capsid protein (cap) and a capsidpolymerase fusion protein (cap-pol) that provides the toxin-coding M-satellites with their transcription and replicase functions. K28 toxin-coding M28-VLPs were isolated, purified and used in vitro for the synthesis of the single-stranded M28 transcript, which was shown to be of plus strand polarity and to bind to oligo(dT)-cellulose, indicating that M28(+)ssRNA contains an internal A-rich tract. Strand separation of the 1.9 kb M28-dsRNA and direct RNA sequencing of its 3′ ends was performed in order to obtain specific DNA oligonucleotides that could be used as primers for cDNA synthesis. The nucleotide sequence of the toxin-coding M28-cDNA identified a single open reading frame (ORF) coding for a polypeptide of 345 amino acids, which contained two potential Kex2p/Kex1p processing sites and three potential sites for protein N-glycosylation. The toxin-coding cDNA was cloned and expressed in sensitive non-killer strains under the control of the yeast PGK promoter. Upon transformation, this construct conferred the complete K28 phenotype, demonstrating that both toxin and immunity determinants are contained within the cloned cDNA. In vitro translational analysis of the M28(+)ssRNA in vitro transcript identified the primary gene product of M28 as a K28 preprotoxin of 38 kDa (M-p38).

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References

  • Bostian KA, Jayachandran S, Tipper DJ (1983) A glycosylated protoxin in killer yeast: models for its structure and maturation. Cell 32:169–180

    Google Scholar 

  • Bostian KA, Elliot Q, Bussey H, Burn V, Smith A, Tipper DJ (1984) Sequence of the preprotoxin dsRNA gene of type 1 killer yeast: multiple processing events produce a two component toxin. Cell 36:741–751

    Google Scholar 

  • Bruenn JA, Brennan V (1980) Yeast viral double-stranded RNAs have heterogenous 3′-termini. Cell 19:923–933

    Google Scholar 

  • Bruenn JA, Bobek L, Brennan V, Held W (1980) Yeast viral RNA polymerase is a transcriptase. Nucleic Acids Res 8:2985–2997

    Google Scholar 

  • Bussey H (1991) K1 killer toxin, a pore-forming protein from yeast. Mol Microbiol 5:2339–2343

    Google Scholar 

  • Bussey H, Boone C, Zhu H, Vernet T, Whiteway M, Thomas DY (1990) Genetic and molecular approaches to synthesis and action of the yeast killer toxin. Experientia 46:193–200

    Google Scholar 

  • Cashdollar LW, Esparza J, Hudson GR, Chmelo R, Lee PKW, Joklik WK (1982) Cloning the double-stranded RNA genes of reovirus: sequence of the cloned S2 gene. Proc Natl Acad Sci USA 79:7644–7648

    Google Scholar 

  • Cashdollar LW, Chmelo R, Esparza J, Hudson GR, Joklik WK (1984) Molecular cloning of the complete genome of reovirus serotype 3. Virology 133:191–196

    Google Scholar 

  • Cooper A, Bussey H (1989) Characterization of the yeast KEX1 gene product: a carboxypeptidase involved in processing secreted precursor proteins. Mol Cell Biol 9:2706–2714

    Google Scholar 

  • Dignard D, Whiteway M, Germain D, Tessier D, Thomas DY (1991) Expression in yeast of a cDNA copy of the K2 killer toxin gene. Mol Gen Genet 227:127–136

    Google Scholar 

  • El-Sherbeini M, Bostian KA (1987) Viruses in fungi: infection of yeast with K1 and K2 killer viruses. Proc Natl Acad Sci USA 84:4293–4297

    Google Scholar 

  • Fujimura T, Esteban R, Wickner RB (1986) In vitro L-A dsRNA synthesis in virus-like particles from Saccharomyces cerevisiae. Proc Natl Acad Sci USA 83:4433–4437

    Google Scholar 

  • Gubler U, Hoffman BJ (1983) A simple and very efficient method for generating cDNA libraries. Gene 25:263–269

    Google Scholar 

  • Hanes SD, Burn VE, Sturley SL, Tipper DJ, Bostian KA (1986) Expression of a cDNA derived from the yeast killer preprotoxin gene: implications for processing and immunity. Proc Natl Acad Sci USA 83:1675–1679

    Google Scholar 

  • Hannig EM, Leibowitz MJ (1985) Structure and expression of the M2 genomic segment of a type 2 killer virus of yeast. Nucleic Acids Res 13:4379–4400

    Google Scholar 

  • Hannig EM, Thiele DJ, Leibowitz MJ (1984) Saccharomyces cerevisiae killer virus transcripts contain template-coded polyadenylate tracts. Mol Cell Biol 4:101–109

    Google Scholar 

  • Haylock RW, Bevan EA (1981) Characterization of the L-dsRNA encoded mRNA of yeast. Curr Genet 4:181–186

    Google Scholar 

  • Icho T, Wickner RB (1989) The double-stranded RNA genome of yeast virus L-A encodes its own putative RNA polymerase by fusing two open reading frames. J Biol Chem 264:6716–6723

    Google Scholar 

  • Ito H, Murata K, Kimura A (1983) Transformation of intact yeast cells treated with alkali cations. J Bacteriol 153:163–168

    Google Scholar 

  • Lolle S, Skipper N, Bussey H, Thomas DY (1984) The expression of cDNA clones of yeast M1 double-stranded RNA in yeast confers both killer and immunity phenotypes. EMBO J 3:1383–1387

    Google Scholar 

  • Maxam AM, Gilbert W (1980) Sequencing end-labeled DNA with base-specific chemical cleavages. Methods Enzymol 65:2985–2997

    Google Scholar 

  • Nemeroff ME, Pietras DF, Bruenn JA (1988) Construction of full-length cDNA copies of viral double-stranded RNA. Virus Genes 1:243–253

    Google Scholar 

  • Nudel U, Soreq H, Littauer UZ, Marbaix G, Huez H, Leclercq M, Hubert E, Chantrenne H (1976) Globin mRNA species containing poly(A) segments of different lengths. Eur J Biochem 64:115–121

    Google Scholar 

  • Sanger F, Nicklen S, Coulson AR (1977) Sequencing with chain-termination inhibitors. Proc Natl Acad Sci USA 74:5463–5467

    Google Scholar 

  • Schmitt MJ, Radler F (1987) Mannoprotein of the yeast cell wall as primary receptor for the killer toxin of Saccharomyces cerevisiae strain 28. J Gen Microbiol 133:3347–3354

    Google Scholar 

  • Schmitt MJ, Radler F (1988) Molecular structure of the cell wall receptor for killer toxin K28 in Saccharomyces cerevisiae. J Bacteriol 170:2192–2196

    Google Scholar 

  • Schmitt MJ, Tipper DJ (1990) K28, a unique double-stranded RNA killer virus of Saccharomyces cerevisiae. Mol Cell Biol 10:4807–4815

    Google Scholar 

  • Schmitt MJ, Tipper DJ (1992) Genetic analysis of maintenance and expression of L and M double-stranded RNAs from yeast killer virus K28. Yeast 8:373–384

    Google Scholar 

  • Schmitt MJ, Brendel M, Schwarz R, Radler F (1989) Inhibition of DNA synthesis in Saccharomyces cerevisiae by yeast killer toxin K28. J Gen Microbiol 135:1529–1535

    Google Scholar 

  • Sherman F, Fink GR, Hicks JB (1983) Methods in yeast genetics, a laboratory manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York

    Google Scholar 

  • Skipper N (1983) Synthesis of a double-stranded cDNA transcript of the killer toxin-coding region of the yeast M1 double-stranded RNA. Biochem Biophys Res Commun 114:518–525

    Google Scholar 

  • Skipper N, Thomas DY, Lau PCK (1984) Cloning and sequencing of the preprotoxin-coding region of the M1-dsRNA. EMBO J 3:107–111

    Google Scholar 

  • Thiele DJ, Leibowitz MJ (1982) Structural and functional analysis of separated strands of killer double-stranded RNA of yeast. Nucleic Acids Res 10:6903–6918

    Google Scholar 

  • Thiele DJ, Hannig EM, Leibowitz MJ (1984) Multiple L doublestranded RNA species of Saccharomyces cerevisiae: evidence for separate encapsidation. Mol Cell Biol 4:92–100

    Google Scholar 

  • Tipper DJ, Schmitt MJ (1991) Yeast dsRNA viruses: replication and killer phenotypes. Mol Microbiol 5:2331–2338

    Google Scholar 

  • Welsh JD, Leibowitz MJ (1980) Transcription of killer virion double-stranded RNA in vitro. Nucleic Acids Res 8:2365–2375

    Google Scholar 

  • Welsh JD, Leibowitz MJ, Wickner RB (1980) Virion DNA-independent RNA polymerase from Saccharomyces cerevisiae. Nucleic Acids Res 8:2349–2363

    Google Scholar 

  • Wickner RB (1992) Double-stranded and single-stranded RNA viruses of Saccharomyces cerevisiae. Annu Rev Microbiol 46:347–375

    Google Scholar 

  • Zhu YS, Zhang XY, Cartwright CP, Tipper DJ (1992) Kex2-dependent processing of yeast K1 killer preprotoxin includes cleavage at ProArg-44. Mol Microbiol 6:511–520

    Google Scholar 

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Communicated by C. Hollenberg

Dedicated to Prof. Ferdinand Radler on the occasion of his 65th birthday

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Schmitt, M.J. Cloning and expression of a cDNA copy of the viral K28 killer toxin gene in yeast. Molec. Gen. Genet. 246, 236–246 (1995). https://doi.org/10.1007/BF00294687

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  • DOI: https://doi.org/10.1007/BF00294687

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