Molecular and functional characterization of Slide, anAc-like autonomous transposable element from tobacco

Abstract

A new transposable element of tobacco, Slide, was isolated from the tl mutant line, which shows somatic instability, after its transposition into a locus encoding nitrate reductase (NR). The Slide-124 element is 3733 bp long and its coding sequences show similarities with conserved domains of the transposases of Ac, Tam3 and hobo. Excision from the NR locus is detectable in somatic leaf tissues and Slide mobility is triggered by in vitro tissue culture. Slide excision events create footprints similar to those left by Ac and Tam3. Tobacco lines derived from the tl mutant line seem characterized by unmethylated copies of a few members of the highly repetitive Slide family. Slide mobility was monitored in transient expression assays. In wild-type tobacco protoplasts, the complete Slide element, as well as a defective copy, is able to excise. The complete Slide element, but not the defective version, is able to excise in protoplasts of the heterologous species lettuce (Lactuca sativa). These results show that Slide carries the functions required for its own mobility, and represents the first autonomous Ac-like element characterized in Solanaceae species.

Extensive, Nonrandom Diversity of Excision Footprints Generated by Ds-Like Transposon Ascot-1Suggests New Parallels with V(D)J Recombination

“…Phenotypic and molecular differences correlated in some instances. Thus, all of the 27 different excision products (14,15, and 18 to 42) that corresponded to the 32 partially colored derivatives exhibited deletions. These extend 120 bp or more 5Ј from the excision site, and color defects increase with deletion size.…”

Folyt1, a New Member of the hAT Family, Is Active in the Genome of the Plant Pathogen Fusarium oxysporum

“…Folyt1 was inserted into the first exon of the nit 1 gene in both mutants CO66 and CO108; therefore, the selection of Nit ϩ revertants will not detect excision events that fail to (Hehl et al, 1991), slide from Nicotiana tabacum (Grappin et al, 1996), Ac from Zea mays (Pohlman et al, 1984), gandalf from Drosophila koepferae (Marin and Fontdevilla, 1995), Gulliver from Chlamydomonas reinhardtii (Ferris, 1989), hermes from Musca domestica (Kempken and Kü ck, 1996), hobo from Drosophila melanogaster (Streck et al, 1986), restless from Tolypocladium inflatum (Kempken and Kü ck, 1996), and Tfo 1 from Fusarium oxysporum (Okuda et al, 1998). Conserved nucleotides are shaded.…”

Mx-rMx, a Family of Interacting Transposons in the GrowinghATSuperfamily of Maize

“…One clade contains the genetically defined elements Ac (Pohlman et al, 1984); (Muller-Neumann et al, 1984), Tam3 (Hehl et al, 1991), and Slide (Grappin et al, 1996) from maize, Antirrhinum, and tobacco (Nicotiana tabacum), respectively, plus several Arabidopsis and rice homologs. Another clade includes Tip100 from morning glory (Ipomoea tricolor; Ishikawa et al, 2002), I-R from maize (W. Eggleston, personal communication), and a transposon from the mosquito Anopheles gambia.…”