ISOLATION OF THE TRANSPOSABLE ELEMENT HUPFER FROM THE ENTOMOPATHOGENIC FUNGUS BEAUVERIA-BASSIANA BY INSERTION MUTAGENESIS OF THE NITRATE REDUCTASE STRUCTURAL GENE

A transposable element has been isolated from the entomopathogenic fun gus Beauveria bassiana by trapping it in the nitrate reductase structu ral gene, which has been cloned from this species. The element had ins erted in the first exon of the nia gene and appeared to have duplicate d the sequence TA at the site of insertion. It was 3336 bp long with 3 0-bp imperfect, inverted, terminal repeats. The element, called hupfer , contained an open reading frame encoding a 321-amino acid protein si milar to the IS630- or mariner-Tcl-like transposases, and a residual s equence of about 2 kb which was not significantly similar to any publi shed sequence. There are fewer than five copies of this transposable e lement present per genome in the fungus.