Integration of multiple repeats of geminiviral DNA into the nuclear genome of tobacco during evolution
Integration of multiple repeats of geminiviral DNA into the nuclear genome of tobacco during evolution
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DOI：
10.1073/pnas.93.2.759
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发表时间：
1996-01-23
影响因子：
11.1
通讯作者：
Lichtenstein, C
中科院分区：
文献类型：
--
作者：
Bejarano, ER;Khashoggi, A;Lichtenstein, C
病毒DNA整合到宿主核基因组中，虽然在细菌和动物系统中并不罕见，但令人惊讶的是，在植物中没有报道。我们已经发现了双生病毒相关DNA（GRD）序列，其形式为包含三个相关重复序列类别的不同的多个同向重复序列组，位于烟草（Nicotiana tabacum）（烟草）核基因组中的独特基因座中，这些序列的组织在我们已经检查的八个不同的烟草栽培品种中是相似或相同的，DNA序列分析揭示每个重复序列具有最类似于新世界双生病毒DNA复制起点加上相邻的编码病毒复制蛋白的AL 1基因的序列，我们相信这些GRD序列最近起源于烟草属进化中，通过非法重组、扩增、缺失和重排过程的某种组合整合双生病毒DNA。这些事件一定发生在随后能够有助于产生配子的分生组织的植物组织中，GRD可能通过选择或随机固定在小的进化群体中保留在烟草中，虽然我们不能检测到这些序列的转录，但这并不排除它们最初可能已经表达的可能性。
Integration of viral DNA into the host nuclear genome, although not unusual in bacterial and animal systems, has surprisingly not been reported for plants, We have discovered geminivirus related DNA (GRD) sequences, in the form of distinct sets of multiple direct repeats comprising three related repeat classes, situated in a unique locus in the Nicotiana tabacum (tobacco) nuclear genome, The organization of these sequences is similar or identical in eight different tobacco cultivars we have examined, DNA sequence analysis reveals that each repeat has sequences most resembling those of the New World geminiviral DNA replication origin plus the adjacent AL1 gene, encoding the viral replication protein, We believe these GRD sequences originated quite recently in Nicotiana evolution through integration of geminiviral DNA by some combination of the processes of illegitimate recombination, amplification, deletions, and rearrangements, These events must have occurred in plant tissue that was subsequently able to contribute to meristematic tissue yielding gametes, GRD may have been retained in tobacco by selection or by random fixation in a small evolving population, Although we cannot detect transcription of these sequences, this does not exclude the possibility that they may originally have been expressed.