title: Recent transposition of yabusame, a novel piggyBac-like transposable element in the genome of the silkworm, Bombyx mori.
abstract: On the W chromosome of the silkworm, Bombyx mori, we found a novel piggyBac-like DNA transposon that potentially encodes an intact transposase (610 amino acid residues), which is flanked by 16-bp perfect inverted terminal repeats and a duplicated TTAA target site. Interestingly, we also identified another intact copy of this transposon on an autosome (chromosome 21), which showed 99.6% identity in the DNA sequence of the transposase (99.3% amino acid identity). These features raised the possibility that this novel piggyBac-like DNA transposon, designated as yabusame, may retain transposition activity. Here we report the identification and characterization of yabusame transposons from the silkworm. We cloned the full length of the yabusame transposon on the W chromosome (yabusame-W) and its autosomal copy (yabusame-1). Southern blot analysis showed that there are interstrain polymorphisms in yabusame elements for their insertion sites and copy number. We also found strong evidence for the recent transposition of yabusame elements in the silkworm genome. Although our in vitro excision assays suggested that the transposition activity of yabusame-1 and yabusame-W has been lost almost entirely, our data will lead to a greater understanding of the characteristics of piggyBac superfamily elements.
authors: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
authors: Takaaki
authors: T
authors: Daimon
authors: Masao
authors: M
authors: Mitsuhiro
authors: Susumu
authors: S
authors: Katsuma
authors: Hiroaki
authors: H
authors: Abe
authors: Kazuei
authors: K
authors: Mita
authors: Toru
authors: T
authors: Shimada
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics*; D002478:Cells, Cultured; D004251:DNA Transposable Elements / Q000235:genetics*; D017344:Genes, Insect; D049750:Genome, Insect / Q000235:genetics*; D008954:Models, Biological; D008969:Molecular Sequence Data; D017385:Sequence Homology; D018411:Spodoptera; D019895:Transposases / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D019895:Transposases