Direct measurement of the transfer rate of chloroplast DNA into the nucleus
Direct measurement of the transfer rate of chloroplast DNA into the nucleus
复制标题
DOI：
10.1038/nature01435
复制
发表时间：
2003-03-06
期刊：
影响因子：
64.8
通讯作者：
Timmis, JN
中科院分区：
文献类型：
--
作者：
Huang, CY;Ayliffe, MA;Timmis, JN
从叶绿体到细胞核的基因转移在进化过程中已经发生（1）。在细胞核中建立功能性基因是罕见的，但没有功能性的DNA转移可能更频繁。本文直接测定了烟草叶绿体DNA（cpDNA）向细胞核的转移速率。为了使这一过程可视化，将核特异性新霉素磷酸转移酶基因（neoSTLS 2）整合到叶绿体基因组中，并通过筛选后代中的卡那霉素抗性幼苗来检测cpDNA向核的转移。用约250，000个后代进行卡那霉素抗性幼苗的筛选，所述后代通过用来自含有cp-neoSTLS 2的植物的花粉使野生型雌性受精而产生。鉴定了16个独立起源的植株，其后代表现出核基因特征的neoSTLS 2的稳定遗传。因此，我们提供了一个定量估计的一个转座事件，在约16,000花粉粒的频率的cpDNA转移到细胞核。除了其在细胞器进化中的明显作用外，叶绿体DNA转座到烟草细胞核中的速率必须对现有的核基因产生重大影响。
Gene transfer from the chloroplast to the nucleus has occurred over evolutionary time(1). Functional gene establishment in the nucleus is rare, but DNA transfer without functionality is presumably more frequent. Here, we measured directly the transfer rate of chloroplast DNA (cpDNA) into the nucleus of tobacco plants (Nicotiana tabacum). To visualize this process, a nucleus-specific neomycin phosphotransferase gene (neoSTLS2) was integrated into the chloroplast genome, and the transfer of cpDNA to the nucleus was detected by screening for kanamycin-resistant seedlings in progeny. A screen for kanamycin-resistant seedlings was conducted with about 250,000 progeny produced by fertilization of wild-type females with pollen from plants containing cp-neoSTLS2. Sixteen plants of independent origin were identified and their progenies showed stable inheritance of neoSTLS2, characteristic of nuclear genes. Thus, we provide a quantitative estimate of one transposition event in about 16,000 pollen grains for the frequency of transfer of cpDNA to the nucleus. In addition to its evident role in organellar evolution, transposition of cpDNA to the nucleus in tobacco occurs at a rate that must have significant consequences for existing nuclear genes.