Induction of telomere-mediated chromosomal truncation and behavior of truncated chromosomes in Brassica napus.

Abstract

Engineered minichromosomes could be stably inherited and serve as a platform for simultaneously transferring and stably expressing multiple genes. Chromosomal truncation mediated by repeats of telomeric sequences is a promising approach for the generation of minichromosomes. In the present work, direct repetitive sequences of Arabidopsis telomere were used to study telomere-mediated truncation of chromosomes in Brassica napus. Transgenes containing alien Arabidopsis telomere were successfully obtained, and Southern blotting and fluorescence insitu hybridization (FISH) results show that the transgenes resulted in successful chromosomal truncation in B.napus. In addition, truncated chromosomes were inherited at rates lower than that predicted by Mendelian rules. To determine the potential manipulations and applications of the engineered chromosomes, such as the stacking of multiple transgenes and the Cre/lox and FRT/FLP recombination systems, both amenable to genetic manipulations through site-specific recombination in somatic cells, were tested for their ability to undergo recombination in B.napus. These results demonstrate that alien Arabidopsis telomere is able to mediate chromosomal truncation in B.napus. This technology would be feasible for chromosomal engineering and for studies on chromosome structure and function in B.napus.