Double-stranded RNA replicons associated with chloroplasts of a green alga, Bryopsis cinicola
Double-stranded RNA replicons associated with chloroplasts of a green alga, Bryopsis cinicola
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DOI：
10.1023/a:1023003412859
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发表时间：
2003-04
影响因子：
5.1
通讯作者：
R. Koga;H. Horiuchi;T. Fukuhara
中科院分区：
文献类型：
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作者：
R. Koga;H. Horiuchi;T. Fukuhara
在多核绿色藻Bryopsis cinicola中发现了与叶绿体和线粒体相关的双链RNA。本文报道了四种叶绿体相关dsRNA（BDRC 1 ~ BDRC 4）的分子特性。其中最长的dsRNA分子（BDRC 1）被完全测序（1959 bp），并在其中发现一个1722 bp的开放阅读框，通过数据库检索发现该开放阅读框的氨基酸序列与几种RNA病毒的RNA依赖性RNA聚合酶（RdRp）序列相似。数据库中最相似的序列是甜菜隐性病毒3的RdRp。系统进化分析表明，BDRC 1的RdRp样序列属于偏体病毒科（Partiviviridae）分支。为了检测这些dsRNA的自主复制，用放线菌素D进行RdRp测定，放线菌素D是DNA依赖性RNA合成的抑制剂。[α-32 P]UTP在叶绿体和线粒体双链RNA中特异性掺入，表明灰拟青霉叶绿体双链RNA（BDRCs）和线粒体双链RNA（BDRM）均为RNA复制子。绿色藻类B. cinicolaB. cinicolaB在其叶绿体和线粒体中含有不同的双链RNA复制子。
Double-stranded RNAs (dsRNAs) associated with chloroplasts and mitochondria have been found in the coenocytic green algaBryopsis cinicola. In this study we report molecular properties of the four chloroplast-associated dsRNAs (BDRC1 to BDRC4) The longest dsRNA molecule (BDRC1) was sequenced entirely (1959 bp) and a single large ORF of 1722 bp was found within it. Database searches revealed similarities between the deduced amino acid sequence of this ORF and RNA-dependent RNA polymerase (RdRp) sequences from several RNA viruses. The most similar sequence in the database was the RdRp of beet cryptic virus 3. Phylogenetic analysis revealed that the RdRp-like sequence of BDRC1 can be placed in the Partitiviridae clade. To detect autonomous replication of these dsRNAs, RdRp assays were carried out with actinomycin D, which is an inhibitor of DNA-dependent RNA synthesis. Incorporation of [α-32P]UTP was detected specifically in the chloroplast and mitochondrial dsRNAs, indicating that both the chloroplast dsRNAs (BDRCs) and the mitochondrial dsRNA (BDRM) ofB. cinicolaare RNA replicons. The green algaB. cinicolaharbors different dsRNA replicons in its chloroplasts and mitochondria.