Structure and dispersion of two truncated Tvv1 grapevine retrotransposons resulting from illegitimate homologous recombination

International audience; Tvv1, a Ty1 copia-like family, was originally reconstituted by a chromosome walking procedure from the grapevine genome. Elements belonging to this family share a highly conserved ORF and LTRs sized between 149 and 157 bp. We later identified a full length Tvv1 copy from a BAC clone, named Tvv1-VB. The structural characteristics of Tvv1-VB are two perfect LTRs 149-bp long and an uninterrupted ORF. In addition, two deleted elements, Tvv1-Δ3460 and Tvv1-Δ3001, were characterized. Compared to Tvv1-VB, Tvv1- Δ3460 and Tvv1-Δ3001 display deletions sized 3,460 bp and 3,001 bp, respectively. The deletion breakpoints were characterized by the presence of boxes 11 and 13-bp long, respectively. In full-length Tvv1-VB, each box corresponds to two short repeats nearly identical that flank the sequence corresponding to the deletion.