title: Transposition of a 600 thousand-year-old LTR retrotransposon in the model legume Lotus japonicus.
abstract: We have identified a new Ty3-gypsy retrotransposon family named LORE2 (Lotus retrotransposon 2) and documented its activity in the model legume Lotus japonicus. Three new LORE2 insertions were found in symbiotic mutant alleles isolated from a plant population, established by tissue culture mediated transformation of the L. japonicus Gifu accession. Low transcriptional and transpositional activities of LORE2 in cultured cells suggested that the LORE2 transpositions identified in the three symbiotic mutants occurred in intact plants, not in callus. Tracing of the transpositional events identified two active LORE2 members in Gifu. One of them named LORE2A possesses a deletion in its coding region and polymorphisms between intraelemental LTRs. LORE2A is thus an aged element, estimated as 600 thousand years old. Our findings indicate that plant genomes carry more cryptic LTR retrotransposons, i.e., aged yet active, than estimated before, and that these cryptic elements may have contributed to plant genome dynamics, for example, the burst of transpositions reported in several plant species.
authors.affiliation: National Institute of Agrobiological Science, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan. efu@nias.affrc.go.jp
authors.forename: Eigo
authors.initials: E
authors.lastname: Fukai
authors.forename: Alicja Dorota
authors.initials: AD
authors.lastname: Dobrowolska
authors.forename: Lene Heegaard
authors.initials: LH
authors.lastname: Madsen
authors.forename: Esben Bjørn
authors.initials: EB
authors.lastname: Madsen
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Umehara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kouchi
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Hirochika
authors.forename: Jens
authors.initials: J
authors.lastname: Stougaard
mesh_terms: D001483:Base Sequence; D015152:Blotting, Northern; D017931:DNA Primers; D019143:Evolution, Molecular; D000070116:Lotus / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012091:Repetitive Sequences, Nucleic Acid; D018626:Retroelements
chemical_list: D017931:DNA Primers; D018626:Retroelements