A proline tRNA(CGG) gene encompassing the attachment site of temperate phage 16-3 is functional and convertible to suppressor tRNA

Authors

  • Béla Blaha,

    1. Institute of Genetics, Agricultural Biotechnology Center, Gödöllõ, Szent-Györgyi A. 4., H-2100, Hungary.
    2. Department of Genetics, Faculty of Science, Eötvös Loránd University and Research Group for Molecular Genetics of Hungarian Academy of Sciences, Budapest, Pázmány P. 1/C., H-1117, Hungary.
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  • Szabolcs Semsey,

    1. Institute of Genetics, Agricultural Biotechnology Center, Gödöllõ, Szent-Györgyi A. 4., H-2100, Hungary.
    2. Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264, USA.
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  • Szilamér Ferenczi,

    1. Institute of Genetics, Agricultural Biotechnology Center, Gödöllõ, Szent-Györgyi A. 4., H-2100, Hungary.
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  • Zsolt Csiszovszki,

    1. Institute of Genetics, Agricultural Biotechnology Center, Gödöllõ, Szent-Györgyi A. 4., H-2100, Hungary.
    2. Department of Genetics, Faculty of Science, Eötvös Loránd University and Research Group for Molecular Genetics of Hungarian Academy of Sciences, Budapest, Pázmány P. 1/C., H-1117, Hungary.
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  • Péter P. Papp,

    1. Institute of Genetics, Agricultural Biotechnology Center, Gödöllõ, Szent-Györgyi A. 4., H-2100, Hungary.
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  • László Orosz

    Corresponding author
    1. Institute of Genetics, Agricultural Biotechnology Center, Gödöllõ, Szent-Györgyi A. 4., H-2100, Hungary.
    2. Department of Genetics, Faculty of Science, Eötvös Loránd University and Research Group for Molecular Genetics of Hungarian Academy of Sciences, Budapest, Pázmány P. 1/C., H-1117, Hungary.
    • E-mail orosz@abc.hu; Tel. (+36) 1 209 0555/8686; Fax (+36) 1 209 0555/1841.

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Summary

Several temperate bacteriophage utilize chromosomal sequences encoding putative tRNA genes for phage attachment. However, whether these sequences belong to genes which are functional as tRNA is generally not known. In this article, we demonstrate that the attachment site of temperate phage 16-3 (attB) nests within an active proline tRNA gene in Rhizobium meliloti 41. A loss-of-function mutation in this tRNA gene leads to significant delay in switching from lag to exponential growth phase. We converted the putative Rhizobium gene to an active amber suppressor gene which suppressed amber mutant alleles of genes of 16-3 phage and of Escherichia coli origin in R. meliloti 41 and in Agrobacterium tumefaciens GV2260. Upon lysogenization of R. meliloti by phage 16-3, the proline tRNA gene retained its structural and functional integrity. Aspects of the co-evolution of a temperate phage and its bacterium host is discussed. The side product of this work, i.e. construction of amber suppressor tRNA genes in Rhizobium and Agrobacterium, for the first time widens the options of genetic study.

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