Characterization of MRT, a new non-LTR retrotransposon in Monascus spp

Abstract

A new non-LTR retrotransposon, named MRT, was discovered in the filamentous fungus Monascus pilosus BCRC38072. The entire nucleotide sequence of the MRT element was 5.5-kb long, including two open reading frames. These two ORFs showed homologies to gag-like and pol-like gene products, and an A-rich sequence at the 3' end of pol-like gene. ORF1 encoded a protein of 5 17 amino acids and contained a cysteine-rich zinc finger motif ORF2 encoded a protein of 1181 amino acids and contained apurinic/apyrimidinic endonuclease (APE), reverse transcriptase (RT), RNaseH domains, and a CCHC motif. The phylogenetic analyses demonstrated that the MRT element should be classified into the Tad1 clade. The results of Southern hybridizations showed that MRT elements were distributed within M pilosus, M ruber, M sanguineus, and M barkeri. In addition, the species of Monascus can be grouped by the presence or absence of MRT elements in the hybridization pattern according to phylogenctic subgroups established with the partial beta-tubulin gene.