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 sequences was central to cancer etiology and research. Although not well documented, transduction of cellular sequences by retroelements has been suggested to modify cellular functions. The maize Bs1 transposon was the first non-vertebrate retroelement reported to have transduced a portion of a cellular gene (c-pma). We show that Bs1 has, in addition, transduced portions of at least two more maize cellular genes, namely for 1,3-beta -glucanase (c-bg) and 1,4-beta -xylan endohydrolase (c-xe). We also show that Bs1 has maintained a truncated gag domain with similarity to the magellan gypsy-like long terminal repeat retrotransposon and a region that may correspond to an env-like domain. Our findings suggest that, like oncogenic retroviruses, the three transduced gene fragments and the Bs1 gag domain encode a fusion protein that has the potential to be expressed. We suggest that transduction by retroelements may facilitate the formation of novel hybrid genes in plants.