Genomic localization of endogenous mobile CACTA family transposons in natural variants of Arabidopsis thaliana
Genomic localization of endogenous mobile CACTA family transposons in natural variants of Arabidopsis thaliana
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DOI：
10.1007/s00438-003-0943-y
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发表时间：
2004-01-01
影响因子：
3.1
通讯作者：
Kakutani, T
中科院分区：
文献类型：
--
作者：
Miura, A;Kato, M;Kakutani, T
富基因区和富转座子区（基因贫乏区）之间的差异是植物基因组的一个共同特征。这可能是由于转座子优先整合到基因贫乏区域，或者可能是由于针对转座子插入到基因丰富区域的净化选择。我们研究了拟南芥CACTA低拷贝数移动亚家族在拟南芥19个自然变异（生态型）基因组中的分布，并将其与DDM1 （DNA甲基化减少）基因突变在实验室诱导的整合模式进行了比较。与移动CACTA1拷贝相似的序列分布在不同的生态型中，在基因组定位中表现出高度的多态性。尽管多态性水平较高，但所有生态型的拷贝数都较低，并且这些元件优先定位于中心周围和富含转座子的区域。这与ddm1突变引起的转位模式形成对比，在ddm1突变中，整合位点的范围偏小，拷贝数经常增加。基于这些观察，我们讨论了自然选择和染色质结构对转座子分布的可能贡献。
The differentiation between gene-rich and transposon-rich (gene-poor) regions is a common feature of plant genomes. This may be due to preferential integration of transposons into gene-poor regions or may be due to purifying selection against transposon insertion into gene-rich regions. We examined the distribution of a low-copy-number mobile subfamily of Arabidopsis CACTA transposons in the genomes of 19 natural variants (ecotypes) of A. thaliana, and compared that to the pattern of integrations induced in the laboratory by mutation of the DDM1 ( Decrease in DNA Methylation) gene. Sequences similar to mobile CACTA1 copies were distributed among the ecotypes and showed high degrees of polymorphism in genomic localization. Despite the high level of polymorphism, the copy number was low in all the ecotypes examined, and the elements were localized preferentially in pericentromeric and transposon-rich regions. This contrasts with the pattern of transposition induced by the ddm1 mutation, in which the range of integration sites is less biased and the copy number frequently increases. Based on these observations, we discuss the possible contribution of natural selection and chromatin structure to the distribution of transposons.