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. 1995 May;7(5):599–609. doi: 10.1105/tpc.7.5.599

The MAR-Mediated Reduction in Position Effect Can Be Uncoupled from Copy Number-Dependent Expression in Transgenic Plants.

L Mlynarova 1, R C Jansen 1, A J Conner 1, W J Stiekema 1, J P Nap 1
PMCID: PMC160807  PMID: 12242378

Abstract

To study the role of matrix-associated regions (MARs) in establishing independent chromatin domains in plants, two transgenes were cloned between chicken lysozyme A elements. These transgenes were the neomycin phosphotransferase (NPTII) gene under control of the nopaline synthase (nos) promoter and the [beta]-glucuronidase (GUS) gene controlled by the double cauliflower mosaic virus (dCaMV) 35S promoter. The A elements are supposed to establish an artificial chromatin domain upon integration into the plant DNA, resulting in an independent unit of transcriptional regulation. Such a domain is thought to be characterized by a correlated and position-independent, hence copy number-dependent, expression of the genes within the domain. The presence of MARs resulted in a higher relative transformation efficiency, demonstrating MAR influence on NPTII gene expression. However, variation in NPTII gene expression was not significantly reduced. The selection bias for NPTII gene expression during transformation could not fully account for the lack of reduction in variation of NPTII gene expression. Topological interactions between the promoter and A element may interfere with the A element as a domain boundary. In contrast, the GUS gene on the same putative chromatin domain showed a highly significant reduction in variation of gene expression, as expected from previous results. Surprisingly, no copy number-dependent GUS gene expression was observed: all plants showed approximately the same GUS activity. We concluded, therefore, that dCaMV 35S-GUS gene expression in mature tobacco plants is regulated by some form of dosage compensation.

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Selected References

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  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. Bonifer C., Yannoutsos N., Krüger G., Grosveld F., Sippel A. E. Dissection of the locus control function located on the chicken lysozyme gene domain in transgenic mice. Nucleic Acids Res. 1994 Oct 11;22(20):4202–4210. doi: 10.1093/nar/22.20.4202. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Breyne P., Gheysen G., Jacobs A., Van Montagu M., Depicker A. Effect of T-DNA configuration on transgene expression. Mol Gen Genet. 1992 Nov;235(2-3):389–396. doi: 10.1007/BF00279385. [DOI] [PubMed] [Google Scholar]
  4. Chuang P. T., Albertson D. G., Meyer B. J. DPY-27:a chromosome condensation protein homolog that regulates C. elegans dosage compensation through association with the X chromosome. Cell. 1994 Nov 4;79(3):459–474. doi: 10.1016/0092-8674(94)90255-0. [DOI] [PubMed] [Google Scholar]
  5. Dean C., Jones J., Favreau M., Dunsmuir P., Bedbrook J. Influence of flanking sequences on variability in expression levels of an introduced gene in transgenic tobacco plants. Nucleic Acids Res. 1988 Oct 11;16(19):9267–9283. doi: 10.1093/nar/16.19.9267. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. 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]
  7. 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]
  8. Huber M. C., Bosch F. X., Sippel A. E., Bonifer C. Chromosomal position effects in chicken lysozyme gene transgenic mice are correlated with suppression of DNase I hypersensitive site formation. Nucleic Acids Res. 1994 Oct 11;22(20):4195–4201. doi: 10.1093/nar/22.20.4195. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. 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]
  10. Lewin B. Chromatin and gene expression: constant questions, but changing answers. Cell. 1994 Nov 4;79(3):397–406. doi: 10.1016/0092-8674(94)90249-6. [DOI] [PubMed] [Google Scholar]
  11. 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]
  12. 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]
  13. 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]
  14. Reitman M., Lee E., Westphal H., Felsenfeld G. Site-independent expression of the chicken beta A-globin gene in transgenic mice. Nature. 1990 Dec 20;348(6303):749–752. doi: 10.1038/348749a0. [DOI] [PubMed] [Google Scholar]
  15. Schlake T., Klehr-Wirth D., Yoshida M., Beppu T., Bode J. Gene expression within a chromatin domain: the role of core histone hyperacetylation. Biochemistry. 1994 Apr 12;33(14):4197–4206. doi: 10.1021/bi00180a012. [DOI] [PubMed] [Google Scholar]
  16. Smith H. A., Swaney S. L., Parks T. D., Wernsman E. A., Dougherty W. G. Transgenic plant virus resistance mediated by untranslatable sense RNAs: expression, regulation, and fate of nonessential RNAs. Plant Cell. 1994 Oct;6(10):1441–1453. doi: 10.1105/tpc.6.10.1441. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. 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]
  18. Strohman R. Epigenesis: the missing beat in biotechnology? Biotechnology (N Y) 1994 Feb;12(2):156–164. doi: 10.1038/nbt0294-156. [DOI] [PubMed] [Google Scholar]
  19. Töpfer R., Matzeit V., Gronenborn B., Schell J., Steinbiss H. H. A set of plant expression vectors for transcriptional and translational fusions. Nucleic Acids Res. 1987 Jul 24;15(14):5890–5890. doi: 10.1093/nar/15.14.5890. [DOI] [PMC free article] [PubMed] [Google Scholar]

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