Hua-Van A, Héricourt F, Capy P, Daboussi M J, Langin T
Institut de Génétique et Microbiologie, Université Paris-Sud, Orsay, France.
Mol Gen Genet. 1998 Sep;259(4):354-62. doi: 10.1007/s004380050822.
The transposable element impala is a member of the widespread superfamily of Tc1-mariner transposons, identified in the genome of the plant pathogenic fungus Fusarium oxysporum. This element is present in a low copy number and is actively transposed in the F. oxysporum strain F24 that is pathogenic for melons. The structure of the impala family was investigated by cloning and sequencing all the genomic copies. The analysis revealed that this family is composed of full-length and truncated copies. Four copies contained a long open reading frame that could potentially encode a transposase of 340 amino acids. The presence of conserved functional domains (a nuclear localisation signal, a catalytic DDE domain and a DNA-binding domain) suggests that these four copies may be autonomous elements. Sequence comparisons and phylogenetic analysis of the impala copies defined three subfamilies, which differ by a high level of nucleotide polymorphism (around 20%). The coexistence of these divergent subfamilies in the same genome may indicate that the impala family is of ancient origin and/or that it arose by successive horizontal transmission events.
转座元件黑斑羚是广泛存在的Tc1-水手转座子超家族的成员，在植物致病真菌尖孢镰刀菌的基因组中被鉴定出来。该元件以低拷贝数存在，并在对甜瓜致病的尖孢镰刀菌菌株F24中活跃转座。通过克隆和测序所有基因组拷贝，对黑斑羚家族的结构进行了研究。分析表明，该家族由全长拷贝和截短拷贝组成。四个拷贝包含一个长开放阅读框，可能编码一个340个氨基酸的转座酶。保守功能域（一个核定位信号、一个催化DDE结构域和一个DNA结合结构域）的存在表明这四个拷贝可能是自主元件。黑斑羚拷贝的序列比较和系统发育分析确定了三个亚家族，它们因高水平的核苷酸多态性（约20%）而不同。这些不同亚家族在同一基因组中的共存可能表明黑斑羚家族起源古老和/或它是通过连续的水平转移事件产生的。
