The rice nuclear genome continuously integrates, shuffles, and eliminates the chloroplast genome to cause chloroplast-nuclear DNA flux
The rice nuclear genome continuously integrates, shuffles, and eliminates the chloroplast genome to cause chloroplast-nuclear DNA flux
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DOI：
10.1105/tpc.104.027706
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发表时间：
2005-03-01
期刊：
影响因子：
11.6
通讯作者：
Obokata, J
中科院分区：
文献类型：
--
作者：
Matsuo, M;Ito, Y;Obokata, J
质体DNA片段通常存在于植物核基因组中，并且DNA从质体到核的转移正在进行中。然而，成功的基因转移是罕见的。如何弥补这一点？为了解决这个问题，我们分析了核定位的质体DNA（nupDNA）片段在整个水稻（水稻粳稻）基因组，相对于他们的年龄，大小，结构和染色体上的整合位点。nupDNA序列与质体基因组序列的差异强烈表明质体DNA在水稻中被反复转移到细胞核中。nupDNA群体的年龄分布概况，以及每个片段的大小和结构特征，揭示了质体DNA一旦整合到核基因组中，它们就会迅速片段化并剧烈改组，令人惊讶的是，其中80%在一百万年内从核基因组中消除。大的nupDNA片段优先定位于染色体的着丝粒周围区域，其中整合和消除频率明显较高。这些数据表明，植物核基因组是在叶绿体基因组的频繁整合和快速消除之间的平衡，并在促进叶绿体核DNA通量的着丝粒周围区域发挥了重要作用。
Plastid DNA fragments are often found in the plant nuclear genome, and DNA transfer from plastids to the nucleus is ongoing. However, successful gene transfer is rare. What happens to compensate for this? To address this question, we analyzed nuclear-localized plastid DNA (nupDNA) fragments throughout the rice (Oryza sativa ssp japonica) genome, with respect to their age, size, structure, and integration sites on chromosomes. The divergence of nupDNA sequences from the sequence of the present plastid genome strongly suggests that plastid DNA has been transferred repeatedly to the nucleus in rice. Age distribution profiles of the nupDNA population, together with the size and structural characteristics of each fragment, revealed that once plastid DNAs are integrated into the nuclear genome, they are rapidly fragmented and vigorously shuffled, and surprisingly, 80% of them are eliminated from the nuclear genome within a million years. Large nupDNA fragments preferentially localize to the pericentromeric region of the chromosomes, where integration and elimination frequencies are markedly higher. These data indicate that the plant nuclear genome is in equilibrium between frequent integration and rapid elimination of the chloroplast genome and that the pericentromeric regions play a significant role in facilitating the chloroplast-nuclear DNA flux.