engleski

Activity of common bean Tpv2 retrotransposon in Arabidopsis thaliana L

LTR-retrotransposons are a family of mobile genetic elements, structuraly and functionaly related to retrovirusis, that transpose via an RNA intermediate. As in retroviruses, the coding region of LTR-retrotransposons is flanked by long direct repeated sequences (LTRs) that are necessary for both transcription and transposition. Although they are ubiquitous constituents of plant genomes and represent a large fraction of some of them (e.g. more than 70% of maize genome), only Tnt1 and Tto1 of tobacco and Tos17 of rice have been demonstrated to be transpositionally active. An impediment to investigation of retrotransposon activity in native host is the considerable background of copies. To circumvent this problem retrotransposons are transfered to heterologous host to investigate their life cycle. Since the Agrobacterium-mediated transformation of plant genome is the most videly used method to transfer transgenes to plant cells, the aim of our study was to investigate the stability of LTR-retrotransposons in A. tumefaciens prior to transfer to plant genome. Two retrotransposons previously shown to be active in plants (Tnt1 and Tto1) and one inactive (Tpv2) element were used in the study. Both active elements appiered to be higly unstable in Agrobacterium. The coding region of both Tnt1 and Tto1 were deleted within two months in Agrobacterium due to homologous recombination between LTRs. In contrast, Tpv2 didn’ t show any instability even after two years in Agrobacterium.

Arabidopsis thaliana L.

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