Chloroplast-Derived Nuclear DNA: Prevalance and Mechanisms of Transposition

我们最近在克隆的番茄核基因的内含子中鉴定了叶绿体衍生的DNA序列。虽然已经通过杂交实验证明，许多植物的核基因组包含来自叶绿体基因组的序列，但这是这种整合物物理分离的第一个例子。我们对整合位点和整合位点的分析表明同源重组机制参与了转位事件。在本提案中，我们概述了旨在物理分离和表征番茄核基因组中许多叶绿体DNA整合的实验。获得的数据将用于验证同源重组涉及到这种叶绿体序列转位到核基因组的假设。DNA序列整合到细胞基因组起源于细胞器基因组的存在已被大量记录。然而，人们对其中的机制知之甚少或一无所知。这项研究的结果应该为这些过程提供深入的见解。

We have recently identified chloroplast-derived DNA sequences in an intron of a tomato nuclear gene that we had cloned. Although it had been demonstrated, by hybridization experiments, that the nuclear genomes of many plants contain sequences derived from the chloroplast genome, this is the first example of the physical isolation of such integrates. Our analysis of the integrates and of the integration sites suggests the involvement of homologous recombination mechanisms in the transposition events. In this proposal we outline experiments designed to physically isolate and characterize many chloroplast DNA integrates in the tomato nuclear genome. The date obtained will be used to test the hypothesis that homologous recombination is involved in the transposition of such chloroplast sequences into the nuclear genome. The presence of DNA sequences integrated into the cellular genome which originated in the organelle genomes has been abundantly documented. However, little or nothing is known about the mechanism(s) involved. The results of this study should provide insight into those processes.