THE ISOLATION OF ANT1, A TRANSPOSABLE ELEMENT FROM ASPERGILLUS-NIGER

A transposable element has been isolated from the industrially importa nt fungus Aspergillus niger (strain N402). The element was identified as an insertion sequence within the coding region of the nitrate reduc tase gene. It had inserted at a TA site and appeared to have duplicate d the target site upon insertion. The isolated element was found to be 4798 bp in length and contained 37-bp inverted, imperfect, terminal r epeats (ITRs). The sequence of the central region of the element revea led an open reading frame (designated ORF1) which showed similarity, a t the amino acid level, to the transposase of the Tc1/mariner class of DNA transposons. Another sequence within the central region of the el ement showed similarity to the 3' coding and downstream untranslated r egion of the amyA gene of A. niger. Sequence homology and structural f eatures indicate that this element, which has been named Ant1 (A. nige r transposon 1), is related to the Tc1/mariner group of DNA transposon s. Ant1 is apparently present as a single copy in strain N402 of A. ni ger.