Firon Arnaud, Villalba François, Beffa Roland, D'Enfert Christophe
Institut Pasteur, Unité Postulante Biologie et Pathogénicité Fongiques, CNRS URA 2172, 75724 Paris Cedex 15, France.
Eukaryot Cell. 2003 Apr;2(2):247-55. doi: 10.1128/EC.2.2.247-255.2003.
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.
机会致病菌烟曲霉是发达国家中导致致命性空气传播真菌感染的最常见病因。为了鉴定新的抗真菌药物靶点，我们研究了烟曲霉基因组中对真菌高效生长所必需的基因。使用一种人工构建的烟曲霉二倍体菌株，其基因组中整合了来自尖孢镰刀菌的一个工程化的黑斑羚160转座子的一个拷贝，通过随机体内转座子诱变来生成二倍体菌株文库。在通过准性遗传学筛选的2386个杂合二倍体菌株中，1.2%的菌株有一个转座元件拷贝整合到了对烟曲霉生长至关重要的一个基因座中。将这些突变体中黑斑羚160侧翼的基因组序列与烟曲霉基因组序列进行比较，得以鉴定出20个以前未被表征的烟曲霉基因。其中，已鉴定出酿酒酵母生长所必需基因的同源物，以及在其他真菌物种中没有同源物的基因。这些结果证实，使用转座元件黑斑羚进行异源转座是子囊菌功能基因组学的一种强大工具，它们为确定烟曲霉中必需基因的完整集合铺平了道路，这是基于靶点开发新型抗真菌药物的第一步。
