Molecular and cytogenetic analyses of stably and unstably expressed transgene loci in tobacco

Victor A. Iglesias, Eduardo A. Moscone, István Papp, Franz Neuhuber, Susan Michalowski, Thomas Phelan, Steven Spiker, Marjori Matzke, Antonius J.M. Matzke

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181 Citations (Scopus)

Abstract

To study the influence of genomic context on transgene expression, we have determined the T-DNA structure, flanking DNA sequences, and chromosomal location of four independent transgene loci in tobacco. Two of these loci were stably expressed in the homozygous condition over many generations, whereas the other two loci became unstable after several generations of homozygosity. The stably expressed loci comprised relatively simple T-DNA arrangements that were flanked on at least one side by plant DNA containing AT-rich regions that bind to nuclear matrices in vitro. Of the unstably expressed loci, one consisted of multiple incomplete T-DNA copies, and the second contained a single intact T-DNA; in beth cases, however, binary vector sequences were directly contiguous to a right T-DNA border. Fluorescence in situ hybridization demonstrated that the two stably expressed inserts were present in the vicinity of telomeres. The two unstably expressed inserts occupied intercalary and paracentromeric locations, respectively. Results on the stability of transgene expression in F1 progeny obtained by intercrossing the four lines and the sensitivity of the four transgene loci to inactivation in the presence of an unlinked 'trans-silencing' locus are also presented. The findings are discussed in the context of repetitive DNA sequences and the allotetraploid nature of the tobacco genome.

Original languageEnglish
Pages (from-to)1251-1264
Number of pages14
JournalPlant Cell
Volume9
Issue number8
DOIs
Publication statusPublished - Aug 1997

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

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    Iglesias, V. A., Moscone, E. A., Papp, I., Neuhuber, F., Michalowski, S., Phelan, T., Spiker, S., Matzke, M., & Matzke, A. J. M. (1997). Molecular and cytogenetic analyses of stably and unstably expressed transgene loci in tobacco. Plant Cell, 9(8), 1251-1264. https://doi.org/10.1105/tpc.9.8.1251