Identification of essential genes in the human fungal pathogen Aspergillus fumigatus by transposon mutagenesis.
The opportunistic pathogen Aspergillus fumigatus is the most frequent cause of deadly airborne fungal infections in developed countries. In order to identify novel antifungal-drug targets, we investigated the genome of A. fumigatus for genes that are necessary for efficient fungal growth. An artificial A. fumigatus diploid strain with one copy of an engineered impala160 transposon from Fusarium oxysporum integrated into its genome was used to generate a library of diploid strains by random in vivo transposon mutagenesis. Among 2,386 heterozygous diploid strains screened by parasexual genetics, 1.2% had a copy of the transposable element integrated into a locus essential for A. fumigatus growth. Comparison of genomic sequences flanking impala160 in these mutants with that of the genome of A. fumigatus allowed the characterization of 20 previously uncharacterized A. fumigatus genes. Among these, homologues of genes essential for Saccharomyces cerevisiae growth have been identified, as well as genes that do not have homologues in other fungal species. These results confirm that heterologous transposition using the transposable element impala is a powerful tool for functional genomics in ascomycota, and they pave the way for defining the complete set of essential genes in A. fumigatus, the first step toward target-based development of new antifungal drugs.
Firon
Arnaud
A
Institut Pasteur, Unité Postulante Biologie et Pathogénicité Fongiques, CNRS URA 2172, 75724 Paris Cedex 15, France.
Villalba
François
F
Beffa
Roland
R
D'Enfert
Christophe
C
D000935:Antifungal Agents / Q000494:pharmacology; D001232:Aspergillus fumigatus / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D001483:Base Sequence / Q000235:genetics; D002874:Chromosome Mapping / Q000379:methods; D004251:DNA Transposable Elements / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000235:genetics*; D018390:Gene Targeting; D016681:Genome, Fungal; D006801:Humans; D016254:Mutagenesis, Insertional / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
D000935:Antifungal Agents; D004251:DNA Transposable Elements; D005656:Fungal Proteins