Lampe D J, Churchill M E, Robertson H M
Department of Entomology, University of Illinois at Urbana-Champaign, 61801, USA.
EMBO J. 1996 Oct 1;15(19):5470-9.
Mariners are a widespread and diverse family of animal transposons. Extremely similar mariners of the irritans subfamily are present in the genomes of three divergent insect host species, which strongly suggests that species-specific host factors are unnecessary for mobility. We tested this hypothesis by examining the activity of a purified transposase from one of these elements (Himar1) present in the horn fly, Haematobia irritans. Himar1 transposase was sufficient to reproduce transposition faithfully in an in vitro inter-plasmid transposition reaction. Further analyses showed that Himar1 transposase binds to the inverted terminal repeat sequences of its cognate transposon and mediates 5' and 3' cleavage of the element termini. Independence of species-specific host factors helps to explain why mariners have such a broad distribution and why they are capable of horizontal transfer between species.
水手转座子是一类广泛存在且多样的动物转座子家族。在三种不同的昆虫宿主物种的基因组中存在着极为相似的激扰亚科水手转座子，这有力地表明物种特异性宿主因子对于转座并非必需。我们通过检测来自角蝇（Haematobia irritans）体内这些元件之一（Himar1）的纯化转座酶的活性来验证这一假设。Himar1转座酶足以在体外质粒间转座反应中忠实地重现转座过程。进一步分析表明，Himar1转座酶与其同源转座子的反向末端重复序列结合，并介导元件末端的5'和3'切割。物种特异性宿主因子的独立性有助于解释为何水手转座子分布如此广泛，以及它们为何能够在物种间进行水平转移。
