Somatic variation during long-term subculturing of plant cells caused by insertion of a transposable element in a phenylalanine ammonia-lyase (PAL) gene

Mol Gen Genet. 1997 Apr 28;254(4):407-16. doi: 10.1007/s004380050433.


We have identified a new En/Spm-like transposable element, Tdc1, in the 5' flanking region of a phenylalanine ammonia-lyase gene (gDcPAL1) that is normally induced by transferring cells of carrot suspension cultures to fresh liquid medium (transfer or dilution effect). The initial integration into gDcPAL1 occurred more than 4 years after culture initiation. Tdc1 was first detected in gDcPAL1 genomic clones of a genomic library made from cells of the same cultured cell line 7 years after its initiation and thus following repeated subculturing. Twelve years after initiation, about 5-10% of the cells had Tdc1 inserted into the gDcPAL1 gene, indicating that Tdc1 insertion into gDcPAL1 occurred in one (or more) cell(s) during the first 4-7 years of subculturing. These mutant cells did not disappear during numerous passages; instead the proportion of cells having this Tdc1 inserted into gDcPAL1 has been increasing over the last 5 years. The promoter activity and the inducibility by transfer/dilution of the gDcPAL1 gene harboring Tdc1 is reduced relative to wild type. Finally, we show that insertion of a transposable element is one of the mechanisms that can cause variation of plant cell cultures during repeated subculture.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Blotting, Southern
  • Cells, Cultured
  • Cloning, Molecular
  • DNA Transposable Elements / genetics*
  • Daucus carota / cytology
  • Daucus carota / enzymology
  • Daucus carota / genetics*
  • Deoxyribonuclease BamHI / metabolism
  • Deoxyribonuclease EcoRI / metabolism
  • Deoxyribonucleases, Type II Site-Specific / metabolism
  • Gene Expression
  • Genes, Plant / genetics
  • Genes, Reporter
  • Genetic Variation*
  • Molecular Sequence Data
  • Open Reading Frames
  • Phenotype
  • Phenylalanine Ammonia-Lyase / genetics*
  • Phenylalanine Ammonia-Lyase / metabolism
  • Promoter Regions, Genetic / genetics
  • Sequence Homology, Amino Acid


  • DNA Transposable Elements
  • Deoxyribonuclease BamHI
  • Deoxyribonuclease EcoRI
  • CTCGAG-specific type II deoxyribonucleases
  • Deoxyribonucleases, Type II Site-Specific
  • Phenylalanine Ammonia-Lyase

Associated data

  • GENBANK/AB001569