Folbos, a new foldback element in rice

A new class I foldback element, Folbos, has been discovered in O.sativa L. Its long terminal inverted repeats (IVRs) are 303 and 331 bp long and the left one encodes a short open reading frame of 76 codons. The IVRs consist of inner and outer domains, the latter built up of 6 tandem repeats of about 30 bp each. The central region is reresented by 90 bp conservative stretch adjacent to a variable length (19-33 bp) A-tail, which in most cases includes the sequence 5’-TGACTT-3’. Folbos targets AT-rich regions and the insertion results in 7 bp target site duplications. Half of the copies found in annotated sequences of O. sativa japonica cv. Nipponbare are positioned in close proximity to (< 1kb) or within the transcribed regions, thus they have the potential to contribute to plant genome evolution.