MATE transposable elements in Aspergillus nidulans: evidence of repeat-induced point mutation

Abstract The sequences of five MATE transposable elements were retrieved from the Aspergillus nidulans genome sequence. These elements are 6.1 kb in length and are characterized by 9–10 bp target site duplications, paired ∼40 bp palindromes close to each end, and in the unmutated elements, 57 clustered Spe-motifs (RWCTAGWY) scattered through their length. Short open reading frames have no known homology. Two of the MATE elements have numerous C → T transitions on both DNA strands relative to the remaining three elements. These mutations have all the characteristics of repeat-induced point mutation (RIP) previously described in Neurospora crassa , but not experimentally demonstrated in A. nidulans . Ninety-eight percent of mutated cytosines are in CpG and CpA doublets, the former mutating at higher frequency. Index descriptors: MATE element; Transposon; Transposable element; RIP; Repeat-induced point mutation; Aspergillus nidulans