T-DNA integration: a mode of illegitimate recombination in plants

EMBO J. 1991 Mar;10(3):697-704.

Abstract

Transferred DNA (T-DNA) insertions of Agrobacterium gene fusion vectors and corresponding insertional target sites were isolated from transgenic and wild type Arabidopsis thaliana plants. Nucleotide sequence comparison of wild type and T-DNA-tagged genomic loci showed that T-DNA integration resulted in target site deletions of 29-73 bp. In those cases where integrated T-DNA segments turned out to be smaller than canonical ones, the break-points of target deletions and T-DNA insertions overlapped and consisted of 5-7 identical nucleotides. Formation of precise junctions at the right T-DNA border, and DNA sequence homology between the left termini of T-DNA segments and break-points of target deletions were observed in those cases where full-length canonical T-DNA inserts were very precisely replacing plant target DNA sequences. Aberrant junctions were observed in those transformants where termini of T-DNA segments showed no homology to break-points of target sequence deletions. Homology between short segments within target sites and T-DNA, as well as conversion and duplication of DNA sequences at junctions, suggests that T-DNA integration results from illegitimate recombination. The data suggest that while the left T-DNA terminus and both target termini participate in partial pairing and DNA repair, the right T-DNA terminus plays an essential role in the recognition of the target and in the formation of a primary synapsis during integration.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Chromosome Deletion
  • DNA Repair
  • DNA, Bacterial / genetics*
  • Genes, Bacterial
  • Models, Genetic
  • Molecular Sequence Data
  • Plants / genetics*
  • Plants / microbiology
  • Recombination, Genetic*
  • Rhizobium / genetics*
  • Sequence Homology, Nucleic Acid

Substances

  • DNA, Bacterial
  • T-DNA

Associated data

  • GENBANK/X51799
  • GENBANK/X53920
  • GENBANK/X53921
  • GENBANK/X53922
  • GENBANK/X53923
  • GENBANK/X53924
  • GENBANK/X53925
  • GENBANK/X56572
  • GENBANK/X57260
  • GENBANK/X57261
  • GENBANK/X57262