A novel hybrid open reading frame formed by multiple cellular gene transductions by a plant long terminal repeat retroelement

The discovery that vertebrate retroviruses could transduce cellular sequenc es was central to cancer etiology and research. Although not well documente d, transduction of cellular sequences by retroelements has been suggested t o modify cellular functions. The maize Bs1 transposon was the first non-ver tebrate retroelement reported to have transduced a portion of a cellular ge ne (c-pma). We show that Bs1 has, in addition, transduced portions of at le ast two more maize cellular genes, namely for 1,3-beta -glucanase (c-bg) an d 1,4-beta -xylan endohydrolase (c-xe). We also show that Bs1 has maintaine d a truncated gag domain with similarity to the magellan gypsy-like long te rminal repeat retrotransposon and a region that may correspond to an env-li ke domain. Our findings suggest that, like oncogenic retroviruses, the thre e transduced gene fragments and the Bs1 gag domain encode a fusion protein that has the potential to be expressed. We suggest that transduction by ret roelements may facilitate the formation of novel hybrid genes in plants.