Hua-Van A, Pamphile J A, Langin T, Daboussi M J
Institut de Génétique et Microbiologie, Université Paris-Sud, Orsay, France.
Mol Gen Genet. 2001 Jan;264(5):724-31. doi: 10.1007/s004380000395.
The impala transposon of Fusarium oxysporum is an active element. We demonstrated that the imp160 copy, transposed into the gene encoding nitrate reductase, is an autonomous element, since it excises from this gene and reinserts at a new genomic position in backgrounds free of active elements. An element in which the transposase gene was replaced by a hygromycin B resistance gene was used (1) to demonstrate the absence of endogenous transposase in several F. oxysporum strains and (2) to check the ability of different genomic copies of impala to transactivate this defective element. This two-component system allowed the identification of autonomous elements in two impala subfamilies and revealed that transactivation can occur between highly divergent elements. We also demonstrate that the autonomous copy transposes in a closely related species complex, F. moniliforme, in a fashion similar to that observed in F. oxysporium. The ability of impala to function as a two-component system and to transpose in a heterologous host promises further advances in our understanding of the factors that modulate transposition efficiency and demonstrates the potential of impala as a means of establishing a transposon tagging system for a wide range of fungal species.
尖孢镰刀菌的黑斑羚转座子是一种活跃元件。我们证明，转座到编码硝酸还原酶基因中的imp160拷贝是一个自主元件，因为它能从该基因中切除并在没有活跃元件的背景下重新插入到新的基因组位置。使用一个转座酶基因被潮霉素B抗性基因取代的元件，（1）证明了几种尖孢镰刀菌菌株中不存在内源性转座酶，（2）检查黑斑羚不同基因组拷贝激活这个缺陷元件的能力。这个双组分系统使得在两个黑斑羚亚家族中鉴定出自主元件，并揭示了转激活可以在高度分化的元件之间发生。我们还证明，自主拷贝在密切相关的物种复合体串珠镰刀菌中以类似于在尖孢镰刀菌中观察到的方式进行转座。黑斑羚作为双组分系统发挥作用以及在异源宿主中转座的能力，有望在我们对调节转座效率的因素的理解上取得进一步进展，并证明了黑斑羚作为为广泛真菌物种建立转座子标签系统手段的潜力。
