A SELF-STABILIZING AC DERIVATIVE AND ITS POTENTIAL FOR TRANSPOSON TAGGING

With the goal of developing a self-stabilizing transposon tagging syst em, a derivative of the maize transposable element Ac (Ds303) harbouri ng a deletion between bp 246 and 736 has been introduced into tomato ( Lycopersicon esculentum) by Agrobacterium tumefaciens-mediated transfo rmation. The deletion removes the major transcription start site, 84 b p of the putative Ac promoter and part of the untranslated leader. Tra nspositions from the T-DNA, where Ds303 was inserted between the manno pine synthase 1' promoter and the GUS gene, were observed in four inde pendent transgenic plants analysed. After transposition the transposed Ds303 elements were stably integrated in the genome and could not tra nsactivate a tester Ds element. However, somatic and germinal transpos itions of the transposed Ds303 elements occurred in the presence of a transposase source.