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Structural instability of a transgene locus in tobacco is associated with aneuploidy. [Erratum: Jan 1997, v. 11 (1), p. 167.]
- Papp, I., Iglesias, V.A., Moscone, E.A., Michalowski, S., Spiker, S., Park, Y.D., Matzke, M.A., Matzke, A.J.M.
- The plant journal 1996 v.10 no.3 pp. 469-478
- Nicotiana sylvestris, Nicotiana tomentosiformis, Nicotiana, Nicotiana tabacum, transgenic plants, loci, aneuploidy, cytogenetics, molecular genetics, chromosomes, chromosome translocation, gene expression, isomerases, karyotyping, plant proteins, gene dosage, nucleotide sequences, genotype
- This paper describes molecular and cytogenetic evidence for the instability of a transgene locus that is present on the triplicated chromosome in an aneuploid tobacco line. This instability was manifested in several ways in trisomics including a major chromosome rearrangement that was detectable cytogenetically, smaller scale DNA rearrangements that occurred both germinally and somatically, and methylation/epigenetic silencing. In a deletion derivative of the locus, DNA breakpoints were found in AT-rich regions. One of these regions binds to nuclear scaffolds in vitro, suggesting a possible role for aberrant topoisomerase II cleavage in destabilization of the locus. The implications of increased chromosome instability in aneuploids for plant karyotype evolution and human carcinogenesis are discussed.