Remobilization of Tol2 transposons in Xenopus tropicalis.
Remobilization of Tol2 transposons in Xenopus tropicalis.
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DOI：
10.1186/1471-213x-10-11
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发表时间：
2010-01-22
影响因子：
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通讯作者：
Mead PE
中科院分区：
文献类型：
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作者：
Yergeau DA;Kelley CM;Kuliyev E;Zhu H;Sater AK;Wells DE;Mead PE
II 类 DNA 转座子是可移动的遗传元件，可将 DNA 序列从基因组中的一个位置移动到另一个位置。我们之前已经证明，来自Oryzias latipes的天然存在的Tol2元件有效地将其相应的非自主转座元件整合到二倍体青蛙热带爪蟾的基因组中。 Tol2 转座子在青蛙基因组中稳定，并以预期的孟德尔频率传递给后代。为了测试整合到热带爪蟾基因组中的 Tol2 转座子是否是再动员的底物，我们将体外转录的 Tol2 mRNA 注射到含有单个 Tol2 转座子拷贝的单细胞胚胎中。对来自两个创始系的注射胚胎的整合位点分析显示，每个胚胎至少有一次体细胞再动员事件。我们还证明，重新动员的转座子通过种系传递，重新整合可以导致在发育中的蝌蚪中产生新的 GFP 表达模式。尽管亲本系包含单个 Tol2 转座子，但由此产生的重新动员蝌蚪经常继承转座子的多个副本。这可能是由于 Tol2 转座酶在 DNA 合成之后但有丝分裂之前的细胞周期期间在发育中的注射胚胎的离散卵裂球中起作用。在这项研究中，我们证明整合到热带爪蟾基因组中的单拷贝 Tol2 转座子是切除和随机重新整合的有效底物，并且重新动员的转座子通过种系传播。这是在这种高度易处理的发育模型生物体中用于插入诱变、基因捕获和增强子捕获筛选的“转座子跳跃”策略发展的重要一步。
The Class II DNA transposons are mobile genetic elements that move DNA sequence from one position in the genome to another. We have previously demonstrated that the naturally occurring Tol2 element from Oryzias latipes efficiently integrates its corresponding non-autonomous transposable element into the genome of the diploid frog, Xenopus tropicalis. Tol2 transposons are stable in the frog genome and are transmitted to the offspring at the expected Mendelian frequency. To test whether Tol2 transposons integrated in the Xenopus tropicalis genome are substrates for remobilization, we injected in vitro transcribed Tol2 mRNA into one-cell embryos harbouring a single copy of a Tol2 transposon. Integration site analysis of injected embryos from two founder lines showed at least one somatic remobilization event per embryo. We also demonstrate that the remobilized transposons are transmitted through the germline and re-integration can result in the generation of novel GFP expression patterns in the developing tadpole. Although the parental line contained a single Tol2 transposon, the resulting remobilized tadpoles frequently inherit multiple copies of the transposon. This is likely to be due to the Tol2 transposase acting in discrete blastomeres of the developing injected embryo during the cell cycle after DNA synthesis but prior to mitosis. In this study, we demonstrate that single copy Tol2 transposons integrated into the Xenopus tropicalis genome are effective substrates for excision and random re-integration and that the remobilized transposons are transmitted through the germline. This is an important step in the development of 'transposon hopping' strategies for insertional mutagenesis, gene trap and enhancer trap screens in this highly tractable developmental model organism.