The transposable element Tan1 of Aspergillus niger var. awamori, a new member of the Fot1 family

Abstract

Aspergillus niger var. awamori has transposable elements that we refer to as Vader and Tan1 (transposon A. niger). Vader was identified by screening unstable nitrate reductase (niaD) mutants for insertions. Four of the isolated niaD mutants were shown to contain a small insertion element. This 437 bp insertion element, Vader, is flanked by 44 bp inverted repeats (IR) and is present in approximately 15 copies in the genomes of two A. niger strains examined. A synthetic 44 bp oligomer of the inverted repeat of Vader has now been used to clone, via the polymerase chain reaction, a 2.3 kb Tan1 element. The Tan1 element has also been isolated from a partial genomic library. Tan1 is present as a single copy in A. niger var. awamori. The Tan1 element has a unique organization: IR-ORF-IR-IR-Vader-IR. The single open reading frame (ORF) (1668 bp) encodes a putative transposase homologous to Fusarium oxysporum Fot1 and Magnaporthe grisea Pot2. Immediately 3' to the second inverted repeat, which bounds the transposase, is a copy of the AT-rich Vader element. We hypothesize that at some stage the independent Vader element, although inactive by itself, arose from Tan1, resulting in current strains with only one copy of Tan1 providing transposase activity and numerous mobile copies of Vader dispersed in the genome.

A Homokaryotic Derivative of a Phanerochaete chrysosporium Strain and Its Use in Genomic Analysis of Repetitive Elements

“…All four members of the Pce family were over 98% identical (30). Although no active progenitor of Pce was detected in P. chrysosporium, the possibility of some biological activity for the Pce sequences cannot be excluded.…”

Minos as a novel Tc1/mariner-type transposable element for functional genomic analysis in Aspergillus nidulans

“…Active Class II transposition events have been described for cut-and-paste elements in several fungi, including the plant pathogen Fusarium oxysporum (Daboussi et al, 1991;Daboussi and Langin, 1994;Langin et al, 1995), Aspergillus niger (Glayzer et al, 1995;Nyyssönen et al, 1996) , Aspergillus fumigatus (Hey et al, 2008) and industrial Aspergillus oryzae strains (Ogasawara et al, 2009). Several Tc1/mariner transposons exist in fungi, but their copy numbers are however lower compared to other eukaryotes (Miskey et al, 2005;Kempken and Kück, 1998;Daboussi and Capy, 2003).…”

DNA transposon fossils present on the conditionally dispensable chromosome controlling AF-toxin biosynthesis and pathogenicity of Alternaria alternata

“…CAD32687), Fcc1 of Cochliobolus carbonum (Panaccione et al 1996), and Tan1 of Aspergillus niger var. awamori (Nyyssönen et al 1996). TLS-S2 (1115 bp) contains seven termination codons and two frameshifts and is shorter than the Molly transposase ORF (1650 bp) due to lack of the 5′ and 3′ regions.…”