Skip to main content
PMC home page
The Plant Cell logoLink to The Plant Cell
. 1996 Sep;8(9):1589–1599. doi: 10.1105/tpc.8.9.1589

Approaching the Lower Limits of Transgene Variability.

L Mlynarova 1, LCP Keizer 1, W J Stiekema 1, J P Nap 1
PMCID: PMC161300  PMID: 12239419

Abstract

The inclusion of chicken lysozyme matrix-associated regions (MARs) in T-DNA has been demonstrated to reduce the variation in [beta]-glucuronidase (GUS) gene expression among first-generation transformed plants. The residual variation observed between transgenic plant lines with MARs at the T-DNA borders was investigated. By definition, any phenotypic variance between or within genetically identical plants is caused by random or environmental variation. This variation therefore sets a lower limit to the variation in GUS activities. The variance of GUS activity in offspring plant populations of genetically identical individuals was used as an estimate of environmental variation. For transgenic plants with MARs at the T-DNA borders, the variation between independent transformants could not be distinguished from the environmental variation. The variation could be attributed mainly to the variation in the GUS activity measurement. Therefore, the MAR element approached the maximal possible reduction of transgene variability given current technology and sample sizes. The role of MARs in offspring plants was evaluated by comparing such populations of transgenic plants for the magnitude of and variation in GUS activity. Pairwise comparisons showed that the presence of MARs reduced variation in offspring generations in the same manner as demonstrated for primary transformants. The populations carrying a doubled cauliflower mosaic virus 35S promoter-GUS gene tended to be more variable than the Lhca3.St.1 promoter-GUS gene-carrying populations. This tendency indicated an intrinsic susceptibility of the doubled cauliflower mosaic virus 35S promoter to variation. Homozygous plants were approximately twice as active as the corresponding hemizygous plants and tended to be more variable than the hemizygous plants. We hypothesized that the magnitude of environmental variations is related to a higher susceptibility to transgene silencing.

Full Text

The Full Text of this article is available as a PDF (975.7 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Allen G. C., Hall G. E., Jr, Childs L. C., Weissinger A. K., Spiker S., Thompson W. F. Scaffold attachment regions increase reporter gene expression in stably transformed plant cells. Plant Cell. 1993 Jun;5(6):603–613. doi: 10.1105/tpc.5.6.603. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bevan M. Binary Agrobacterium vectors for plant transformation. Nucleic Acids Res. 1984 Nov 26;12(22):8711–8721. doi: 10.1093/nar/12.22.8711. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Dorer D. R., Henikoff S. Expansions of transgene repeats cause heterochromatin formation and gene silencing in Drosophila. Cell. 1994 Jul 1;77(7):993–1002. doi: 10.1016/0092-8674(94)90439-1. [DOI] [PubMed] [Google Scholar]
  4. Dorlhac de Borne F., Vincentz M., Chupeau Y., Vaucheret H. Co-suppression of nitrate reductase host genes and transgenes in transgenic tobacco plants. Mol Gen Genet. 1994 Jun 15;243(6):613–621. doi: 10.1007/BF00279570. [DOI] [PubMed] [Google Scholar]
  5. Heslop-Harrison J. S. Nuclear architecture in plants. Curr Opin Genet Dev. 1992 Dec;2(6):913–917. doi: 10.1016/s0959-437x(05)80115-7. [DOI] [PubMed] [Google Scholar]
  6. Hobbs S. L., Warkentin T. D., DeLong C. M. Transgene copy number can be positively or negatively associated with transgene expression. Plant Mol Biol. 1993 Jan;21(1):17–26. doi: 10.1007/BF00039614. [DOI] [PubMed] [Google Scholar]
  7. Laemmli U. K., Käs E., Poljak L., Adachi Y. Scaffold-associated regions: cis-acting determinants of chromatin structural loops and functional domains. Curr Opin Genet Dev. 1992 Apr;2(2):275–285. doi: 10.1016/s0959-437x(05)80285-0. [DOI] [PubMed] [Google Scholar]
  8. Matzke M. A., Matzke AJM. How and Why Do Plants Inactivate Homologous (Trans)genes? Plant Physiol. 1995 Mar;107(3):679–685. doi: 10.1104/pp.107.3.679. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Mlynarova L., Jansen R. C., Conner A. J., Stiekema W. J., Nap J. P. The MAR-Mediated Reduction in Position Effect Can Be Uncoupled from Copy Number-Dependent Expression in Transgenic Plants. Plant Cell. 1995 May;7(5):599–609. doi: 10.1105/tpc.7.5.599. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Mlynarova L., Loonen A., Heldens J., Jansen R. C., Keizer P., Stiekema W. J., Nap J. P. Reduced Position Effect in Mature Transgenic Plants Conferred by the Chicken Lysozyme Matrix-Associated Region. Plant Cell. 1994 Mar;6(3):417–426. doi: 10.1105/tpc.6.3.417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Nap J. P., van Spanje M., Dirkse W. G., Baarda G., Mlynarova L., Loonen A., Grondhuis P., Stiekema W. J. Activity of the promoter of the Lhca3.St.1 gene, encoding the potato apoprotein 2 of the light-harvesting complex of Photosystem I, in transgenic potato and tobacco plants. Plant Mol Biol. 1993 Nov;23(3):605–612. doi: 10.1007/BF00019307. [DOI] [PubMed] [Google Scholar]
  12. Peach C., Velten J. Transgene expression variability (position effect) of CAT and GUS reporter genes driven by linked divergent T-DNA promoters. Plant Mol Biol. 1991 Jul;17(1):49–60. doi: 10.1007/BF00036805. [DOI] [PubMed] [Google Scholar]
  13. Spiker S., Thompson W. F. Nuclear Matrix Attachment Regions and Transgene Expression in Plants. Plant Physiol. 1996 Jan;110(1):15–21. doi: 10.1104/pp.110.1.15. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Stief A., Winter D. M., Strätling W. H., Sippel A. E. A nuclear DNA attachment element mediates elevated and position-independent gene activity. Nature. 1989 Sep 28;341(6240):343–345. doi: 10.1038/341343a0. [DOI] [PubMed] [Google Scholar]

Articles from The Plant Cell are provided here courtesy of Oxford University Press

RESOURCES