Dramatic amplification of a rice transposable element during recent domestication
Dramatic amplification of a rice transposable element during recent domestication
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DOI：
10.1073/pnas.0605421103
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发表时间：
2006-11-21
影响因子：
11.1
通讯作者：
Wessler, Susan R.
中科院分区：
文献类型：
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作者：
Naito, Ken;Cho, Eunyoung;Wessler, Susan R.
尽管在高等真核生物的基因组中普遍存在转座因子，但实际上尚不清楚它们如何在不杀死宿主的情况下扩增到非常高的拷贝数。在这里，我们报告了在4个水稻品系中发现微型倒置重复转座元件（mPing）从大约50个拷贝扩增到大约1000个拷贝的水稻品系。我们对280个插入进行了鉴定，发现70%的插入位于编码区5kb内，但插入外显子和内含子的数量明显不足。对基因表达和转座元件活性的进一步分析表明，mPing获得高拷贝数的能力是由于三个因素：(i)对有害插入的快速选择，（ii）剩余插入对基因转录的中性或最小影响，以及（iii） mPing元件在已经拥有1000个拷贝的菌株中的持续迁移。本研究记录的mPing拷贝数的快速增加代表了水稻等自交受精植物种群多样性的潜在有价值的来源。
Despite the prevalence of transposable elements in the genomes of higher eukaryotes, what is virtually unknown is how they amplify to very high copy numbers without killing their host. Here, we report the discovery of rice strains where a miniature inverted-repeat transposable element (mPing) has amplified from approximate to 50 to approximate to 1,000 copies in four rice strains. We characterized 280 of the insertions and found that 70% were within 5 kb of coding regions but that insertions into exons and introns were significantly underrepresented. Further analyses of gene expression and transposable-element activity demonstrate that the ability of mPing to attain high copy numbers is because of three factors: (i) the rapid selection against detrimental insertions, (ii) the neutral or minimal effect of the remaining insertions on gene transcription, and (iii) the continued mobility of mPing elements in strains that already have > 1,000 copies. The rapid increase in mPing copy number documented in this study represents a potentially valuable source of population diversity in self-fertilizing plants like rice.