The expression of open reading frames located on the subgenomic RNA (sgRNA) has been studied in an in vitro transcription and translation system. The obtained results indicate: a) translation of sgRNA occurs according to the scanning model since the insertion of a palindrome (AGo = -61 kcal/mol) prevents the initiation of translation; b) ORF6 is translated by suppression of the stop codon separating ORF4 from ORF6 and the presence of suppressor tRNA is necessary for the read through; c) the presence of leader sequence of sgRNA (212 nucleotides) decreases the translation efficiency of ORFs located downstream and it afTects the ratio of products of ORF4 and ORF5; d) 3UTR does not influence on an expression of genes located on the sgRNA.
2. Mayo, M.A. & Ziegler-Graff, V. (1996) Molecular Biology of luteoviruses. Ack>. Virus Res. 46, 416-460.
3. Bahner, I., Lamb, J., Mayo, M.A. & Hay, R.T. (1990) Expression of the genome of potato leafroll virus: Readthrough of the coat protein termination codon in vivo. J. Gen. Virol. 71, 2251-2256.
4. Tacke, E., Prufer, D., Salamini, F. & Rohde, W. (1990) Characterization of a potato leafroll luteovirus subgenomic RNA: Differential expression by internal translation initiation and UAG suppression. J. Gen. Virol. 71, 2265 2272.
5. Sambrook, J., Fritsch, E.F. & Maniatis, T. (1989) Molecular Cloning: A Laboratory Man ual; 2nd edn., Cold Spring Harbor Laboratory, Cold Spring Harbor, NY.
6. Palucha, A, Sadowy, E., Kujawa, A., Juszczuk, M., Zagorski, W. & Hulanicka, D. (1994) Nucleotide sequence of RNA of a Polish isolate of potato leafroll luteovirus. Acta Biochim. Polon. 41, 405-414.
7. Sadowy, E., Palucha, A.H., Gronenbom, B., Zag6rski, W. & Hulanicka. D.M. (1994) Constructing infectious transcripts of potato leaf- roll virus. Plants and viruses: Partners in pathogenicity. International Conference: 17-21 July, Grignon, France, Abstract.
8. Kujawa, A.B., Drugeon, G., Hulanicka, M.D. & Haenni, A.-L. (1993) Structural requirements for efficient translational frameshift- ing in the synthesis of the putative viral RNA- dependent RNA polymerase of potato leafroll virus. Nucleic Acids Res. 21, 2165-2171.
9. Kozak, M. (1989) The scanning model for translation: An update. J. Cell Biol. 108. 229-241.
10. Herman, R.C. (1989) Alternatives for the initiation of translation. Trends Biochem. Sci. 14, 219-222.
11. Macejak, D.G. & Sarnow, P. (1991) Internal initiation of translation mediated by the 5' leader of cellular mRNA Nature 353, 90-94.
12. Reutenaur, A., Ziegler-Graff, V., Lot, H., Scheidecker, D., Guilley, H., Richards, K. & Jonard, G. (1993) Identification of beet western yellows luteovirus genes implicated in viral replication and particle morphogenesis. Virology 195, 692-699.
13. Dinesh-Kumar, S.P., Brault, V. & Miller, W.A. (1992) Precise mapping and in vitro translation of a Afunctional subgenomic RNA of barley yellow dwarf virus. Virology 187, 711-722.
14. Davies, LW. & Wilson, T.M.A. (1992) Genetic Engineering with Plant Viruses. CRC Press, Inc. Boca Raton, F1
15. Rochon, D.M. & Johnston, J.C. (1991) Infectious transcripts from cloned cucumber necrosis virus cDNA: Evidence for a Afunctional subgenomic mRNA. Virology 181, 656-665.
16. Veidt, I., Lot, H.. Leiser, M., Scheidecker, D., Guilley, H., Richards, K. & Jonard, G. (1988) Nucleotide sequence of beet western yellows virus RNA. Nucleic Acids Res. 16,9917-9932.
17. Miller, J.S. & Mayo, M.A. (1991) The location of the 5' end of the potato leafroll luteovirus subgenomic coat protein mRNA. J. Gen. Virol. 72, 2633-2638.
18. Skuzeski, J.M., Lindy, M.N., Gesteland, R.F. & Atkins, J.F. (1991) The signal for leaky UAG stop codon in several plant viruses includes the two downstream codons. J. Mol. Biol. 218, 365-373.
19. Brown, C M., Dinesh-Kumar, S.P. & Miller, W.A. (1996) Local and distant sequences are required for efficient readthrough of the barley yellow dwarf virus PAVcoat protein gene stop codon. J. Virol. 70, 5884-5892.
20. Gallie, D.R., Sleat, D.E., Watts, J.W., Turner, P.C. & Wilson, T.M.A. (1987) The 5' leader sequence of tobacco mosaic virus RNA enhances the expression of foregin gene transcripts in vitro and in vivo. Nucleic Acids Res. 15, 3257-3273.
21. Jobling, S.A. & Gehrke, L. (1987) Enhanced translation of chimeric messenger RNAs containing a plant viral untranslated leader sequence. Nature 325, 622-625.
22. Gallie, D R., Sleat, D.E., Watts, J.W., Turner, P.C. & Wilson, T.M.A. (1987) A comparison of eukaryotic viral 5' leader sequences as enhancers of mRNA expression in vivo. Nucleic Acids Res. 15,8693-8711.
23. Zelenina, D.A., Kulaeva, O.L., Smirnyagina, E.V., Solovyev, A.G., Miroshnichenko, N.A., Fedorkin, O.N., Rodionova, N.P., Morozov, S.Yu. & Atabekov, J.G. (1992) Translation enhancing properties of the 5'-leader of potato virus X genomic RNA. FEBS Lett. 296. 267-270.
24. Jobling, S.A., Cuthbert, C M., Rogers, S.G., Fraley, R.T., Gehrke, L. (1988) In vitro transcription and translation efficiency of chimeric SP6 messenger RNAs devoid of 5' vector nucleotides. Nucleic Acids Res. 16. 4483-4498.
25. Zuker, M. & Stiegler, P. (1981) Optimal computer folding of large RNA sequences using thermodynamics and auxiliary information. Nucleic Acids Res. 9, 2197-2206.