A reciprocal translocation, induced by a canonical integration of a single T-DNA, interrupts the HMG-I/Y Arabidopsis thaliana gene.
Major chromosomal rearrangements occur during Arabidopsis thaliana T-DNA transformation. They generally result from interactions between multiple T-DNA copies during the integration process or from aborted integration events. We report here a reciprocal translocation associated with the integration of a single T-DNA which otherwise shows all the characteristic features of a canonical integration event. The exchanged fragments roughly correspond to half of the left arm of chromosome 1 and to two thirds of the right arm of chromosome 2. The chromosome 1 breakpoint maps close to position 23.6 cM and interrupts the coding sequence of the HMG-I/Y gene, which is present at a single copy in the Arabidopsis genome and encodes a non-histone chromosomal protein putatively involved in regulation of gene expression. The chromosome 2 breakpoint maps close to position 33.6 cM, and is located 419 bp upstream of a gene encoding a putative homeodomain transcription factor. Homozygotes for the translocation display a severe phenotype with major developmental abnormalities and total sterility, while heterozygotes are fertile, most of them showing a wild-type phenotype. Among the six possible unbalanced genotypic classes, four are entirely lethal while only a few individuals from the two others survive. Analysis of relations between phenotypes and genotypes strongly suggests that the major phenotypic alterations observed do not result from inactivation of the HMG-I/Y gene.
Lafleuriel
Jacqueline
J
GEEM-BIOMOVE, Université Blaise-Pascal, CNRS UMR 6547, 24, avenue des Landais, 63177 Aubière cedex, France.
Degroote
Fabienne
F
Depeiges
Annie
A
Picard
Georges
G
D017360:Arabidopsis / Q000235:genetics*; D001483:Base Sequence; D032461:Chromosomes, Plant / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics*; D005838:Genotype; D025741:HMGA1a Protein / Q000235:genetics*; D007612:Kanamycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D010641:Phenotype; D017422:Sequence Analysis, DNA; D014178:Translocation, Genetic
D004269:DNA, Bacterial; C036483:T-DNA; D025741:HMGA1a Protein; D007612:Kanamycin