Polyuridylylation and processing of transcripts from multiple gene minicircles in chloroplasts of the dinoflagellate Amphidinium carterae
Polyuridylylation and processing of transcripts from multiple gene minicircles in chloroplasts of the dinoflagellate Amphidinium carterae
复制标题
DOI：
10.1007/s11103-012-9916-z
复制
发表时间：
2012-07-01
影响因子：
5.1
通讯作者：
Howe, Christopher J.
中科院分区：
文献类型：
--
作者：
Barbrook, Adrian C.;Dorrell, Richard G.;Howe, Christopher J.
尽管植物叶绿体中的转录和转录加工已经被广泛地表征，但真核生物中其他叶绿体谱系的RNA代谢仍然知之甚少。本文利用RT-PCR技术研究了典型的含佩草苷甲藻（Amphidinium carterae）叶绿体的转录和转录加工。这些生物具有非常不寻常的叶绿体基因组，其基因位于多个小的“迷你环”元件上，并且具有许多特殊的RNA代谢特征，包括通过滚动环机制转录和转录物的3'端多尿苷化。我们证明了a . carterae的转录是通过一个旋转环机制发生的，正如之前在鞭毛藻Heterocapsa中所显示的那样，并提供了a . carterae微环产生多反反子转录本和单反子转录本的证据，包括一些以前未知的含有orf的区域。我们证明了在A. carterae中存在多尿酰化和非多尿酰化转录本，并表明多顺反电子转录本可以最终被多尿酰化。我们提出了一个在鞭毛藻叶绿体中RNA代谢的模型，其中长多顺反电子前体被加工成成熟的转录本。末端多尿酰化可以用正确的3'端标记转录本。
Although transcription and transcript processing in the chloroplasts of plants have been extensively characterised, the RNA metabolism of other chloroplast lineages across the eukaryotes remains poorly understood. In this paper, we use RT-PCR to study transcription and transcript processing in the chloroplasts of Amphidinium carterae, a model peridinin-containing dinoflagellate. These organisms have a highly unusual chloroplast genome, with genes located on multiple small 'minicircle' elements, and a number of idiosyncratic features of RNA metabolism including transcription via a rolling circle mechanism, and 3' terminal polyuridylylation of transcripts. We demonstrate that transcription occurs in A. carterae via a rolling circle mechanism, as previously shown in the dinoflagellate Heterocapsa, and present evidence for the production of both polycistronic and monocistronic transcripts from A. carterae minicircles, including several regions containing ORFs previously not known to be expressed. We demonstrate the presence of both polyuridylylated and non-polyuridylylated transcripts in A. carterae, and show that polycistronic transcripts can be terminally polyuridylylated. We present a model for RNA metabolism in dinoflagellate chloroplasts where long polycistronic precursors are processed to form mature transcripts. Terminal polyuridylylation may mark transcripts with the correct 3' end.