Tfo1: an Ac -like transposon from the plant pathogenic fungus Fusarium oxysporum

Abstract

A transposable element from a plant pathogenic fungus, Fusarium oxrysporum, was isolated and characterized. Four clones carrying moderately repetitive DNA were selected from a genomic library of the strain MAFF305118 of F. oxysporum f. sp. lagenariae, which causes wilt of bottle gourd. One the four clones was found to include a transposable element, which we have named Tfo1. This element is 2763 bp in size and appears to contain a long ORF that can encode a polypeptide of 777 amino acids. The amino acid sequence shows significant similarity to transposases from the hAT family of transposons, such as the maize transposon Activator (Ac). The element has 15-bp terminal inverted repeats and causes an 8-bp target site duplication upon insertion, as expected for an hAT-family transposon. Northern analysis detected a transcript, which hybridized to the putative transposase-encoding region of Tfo1. The size of this transcript (about 2.3 kb) corresponds to that of the ORF. A Southern analysis using pulsed-field gel electrophoresis showed that multiple chromosomal bands carry Tfo1 elements. PCR amplification of the Tfo1 elements with a 15-base inverted repeat primer produced a single DNA fragment of about 2.8 kb in all bottle gourd-infecting strains used. The element was found in multiple copies in the genome of all these strains and also in strains from other formae speciales tested. The sequence similarity of the Tfo1 element to other transposons, together with its transcriptional expression and genomic distribution, strongly suggests that Tfo1 is a member of the hAT transposon family.

FoSTUA, Encoding a Basic Helix-Loop-Helix Protein, Differentially Regulates Development of Three Kinds of Asexual Spores, Macroconidia, Microconidia, and Chlamydospores, in the Fungal Plant PathogenFusarium oxysporum

“…Isolation of total DNA from F. oxysporum and DNA gel blot hybridization were performed as previously described (25,38). Isolation of total RNA from F. oxysporum, preparation of poly(A) ϩ RNA, and RNA gel blot hybridization were performed as previously described (42,43).…”

Hop, an Active Mutator-like Element in the Genome of the Fungus Fusarium oxysporum

“…The fact that Hop insertion does not determine a visible mutant phenotype suggests that this gene is not essential in F. oxysporum and/or is present in more than one copy. Additionally, a second Hop element is located 184 bp downstream of an ORF that we have partially sequenced, which encodes a putative protein strongly similar to transposases from fungal Ac-like transposons such as Tfo1 of F. oxysporum (Okuda et al 1998) and restless from Tolypocladium inflatum (Kempken and Kück 1996). This ORF is 99% identical to the putative product of a repetitive sequence (GenBank accession number X82490.1) reported to be responsible for the disruption of an F. oxysporum cytochrome P450 gene (Mouyna 1994).…”

Wsp1, a GBD/CRIB Domain-Containing WASP Homolog, Is Required for Growth, Morphogenesis, and Virulence of Cryptococcus neoformans

“…In the plant model Arabidopsis thaliana, no WASP homolog was found, but instead a family of WAVE (verprolin-homologous) proteins that function to promote actin nucleation were found (15). The WAVE proteins also exist in mammals and, in contrast to WASPs that are activated by Cdc42, WAVE proteins are regulated by Rac (23). In fungi, S. cerevisiae Las17/Bee1, Schizosaccharomyces pombe Wsp1, and Candida albicans Wal1 are WASP homologs that lack the GBD/CRIB domain (9,17,18,32).…”