Casse N, Bui Q T, Nicolas V, Renault S, Bigot Y, Laulier M
Laboratoire de Biologie et Génétique Evolutive, EA 3265, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans cedex, France.
Mol Phylogenet Evol. 2006 Aug;40(2):609-19. doi: 10.1016/j.ympev.2006.02.005. Epub 2006 May 11.
Mariner-like elements (MLEs) have been widely detected in terrestrial species. The first complete MLE isolated from a marine invertebrate was detected in the genome of the hydrothermal crab Bythograea thermydron by Halaimia-Toumi et al. [Halaimia-Toumi, N., Casse, N., Demattei, M.V., Renault, S., Pradier, E., Bigot, Y., Laulier, M., 2004. The GC-rich transposon Bytmar1 from the deep-sea hydrothermal crab, Bythograea thermydron, may encode three transposase isoforms from a single ORF. J. Mol. Evol. 59, 747-760] and called Bytmar1. Here, we report the isolation of three new Bytmar1 relatives from the genomes of one hydrothermal amphipod Ventiella sulfuris (Vensmar1) and two coastal crustacea, Maia brachydactila (Maibmar1) and Cancer pagurus (Canpmar1). Like Bytmar1, these MLEs have an unusually high GC content, a high CpG ratio, and a low TpA ratio. Their consensus sequence encodes a transposase that is preceded by an N-flag, as in Bytmar1, which could be a marine feature. Only one of the 19 clones obtained, Vensmar1.3, encoded for a full-length transposase. The phylogenetic analyses revealed that all these Bytmar1-related elements can be differentiated into two clusters, corresponding to the coastal or hydrothermal origin of their hosts. They also confirmed that the irritans sub-family comprises at least four lineages that seem to depend on the taxonomical position and habitat of their hosts. Finally, we observed that elements coding for two potentially complete transposases exhibiting 99.5% similarity, Bytmar1.11 and Vensmar1.3, were present in the genome of two distantly related hydrothermal crustacea, one Amphipod and one Decapod. The hypothesis of horizontal transfers is discussed in the light of the sequence similarities observed.
水手样元件（MLEs）已在陆生生物中被广泛检测到。从海洋无脊椎动物中分离出的首个完整MLE是由哈拉米亚 - 图米等人在热液蟹Bythograea thermydron的基因组中检测到的[哈拉米亚 - 图米，N.，卡斯，N.，德马泰，M.V.，雷诺，S.，普拉迪耶，E.，比戈，Y.，劳利耶，M.，2004年。来自深海热液蟹Bythograea thermydron的富含GC的转座子Bytmar1可能从单个开放阅读框编码三种转座酶同工型。《分子进化杂志》59，747 - 760]，并将其命名为Bytmar1。在此，我们报告从一种热液双足虾Ventiella sulfuris（Vensmar1）以及两种沿海甲壳类动物——短指蝉蟹Maia brachydactila（Maibmar1）和黄道蟹Cancer pagurus（Canpmar1）的基因组中分离出三种新的Bytmar1相关元件。与Bytmar1一样，这些MLEs具有异常高的GC含量、高的CpG比率和低的TpA比率。它们的共有序列编码一种转座酶，该转座酶前面有一个N - 标记，如同在Bytmar1中一样，这可能是一种海洋特征。在获得的19个克隆中，只有一个，即Vensmar1.3，编码全长转座酶。系统发育分析表明，所有这些与Bytmar1相关的元件可分为两个簇，对应于其宿主的沿海或热液起源。分析还证实，irritans亚家族至少包括四个谱系，这似乎取决于其宿主的分类地位和栖息地。最后，我们观察到编码两种具有99.5%相似性的潜在完整转座酶的元件，即Bytmar1.11和Vensmar1.3，存在于两种远缘热液甲壳类动物的基因组中——一种是双足虾，另一种是十足目动物。根据观察到的序列相似性对水平转移假说进行了讨论。
