CHLOROPLAST MRNAS ARE 30 POLYURIDYLYLATED IN THE GREEN ALGA PITHOPHORA ROETTLERI (CLADOPHORALES)
CHLOROPLAST MRNAS ARE 30 POLYURIDYLYLATED IN THE GREEN ALGA PITHOPHORA ROETTLERI (CLADOPHORALES)
复制标题
绿藻 Pithophora Roettleri (ClADOPHORALES) 中的叶绿体 MRNAS 经 30 聚脲酰化
DOI：
10.1111/jpy.13033-20-051
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发表时间：
2020
影响因子：
2.9
通讯作者：
Cahoon, AB
中科院分区：
文献类型：
--
作者：
Meade, MJ;Proulex, GCR;Manoylov, KM;Cahoon, AB
绿色藻类刚毛藻目中的物种具有非常规的质体结构，其中单个编码区或少量基因以折叠成发夹结构的线性单链DNA的形式存在。另一类叶绿体基因组同样减少的光合生物是多甲藻甲藻，其质体是携带光合作用所需的一个或几个基因的小环。在多甲藻甲藻和绿藻类中，一个不寻常的方面是多甲藻甲藻mRNA 3′端的多尿苷酰化。进行这项研究是为了了解非常规的高度还原的质体结构是否与非常规的RNA加工共同发生。为了解决这个问题，我们分析了Pithophora roettleri（刚毛藻目）已知叶绿体基因的5′和3′ mRNA末端，以寻找转录后加工的证据。采用环形逆转录酶PCR（cRT-PCR）和扩增子深度测序分析5′和3′ mRNA末端。收集了几个加工事件的证据，最值得注意的是，8个基因中有6个的3′末端是多尿苷酰化的，这在泡孔动物以外的任何谱系中都没有报道。其他加工事件包括poly（A）和杂聚3′添加、5′初级转录起始位点以及环化RNA的存在。代表其他绿色藻类谱系的其他五个物种也进行了测试，聚（U）添加似乎仅限于刚毛藻目。这些结果表明，叶绿体mRNA的polyuridylation是不是唯一的来源光合泡状体，并可能有收敛进化在两个不同的光合谱系。
Species within the green algal order Cladophorales have an unconventional plastome structure where individual coding regions or small numbers of genes occur as linear single‐stranded DNAs folded into hairpin structures. Another group of photosynthetic organisms with an equivalently reduced chloroplast genome are the peridinin dinoflagellates of the Alveolata eukaryotic lineage whose plastomes are mini‐circles carrying one or a few genes required for photosynthesis. One unusual aspect of the Alveolata is the polyuridylylation of mRNA 3′ ends among peridinin dinoflagellates and the chromerid algae. This study was conducted to understand if an unconventional highly reduced plastome structure co‐occurs with unconventional RNA processing. To address this, the 5′ and 3′ mRNA termini of the known chloroplast genes ofPithophora roettleri(order Cladophorales) were analyzed for evidence of post‐transcriptional processing. Circular Reverse Transcriptase PCR (cRT‐PCR) followed by deep sequencing of the amplicons was used to analyze 5′ and 3′ mRNA termini. Evidence of several processing events were collected, most notably the 3′ termini of six of the eight genes were polyuridylylated, which has not been reported for any lineage outside of the Alveolata. Other processing events include poly(A) and heteropolymeric 3′ additions, 5′ primary transcript start sites, as well as the presence of circularized RNAs. Five other species representing other green algal lineages were also tested and poly(U) additions appear to be limited to the order Cladophorales. These results demonstrate that chloroplast mRNA polyuridylylation is not the sole provenance of photosynthetic alveolates and may have convergently evolved in two distinct photosynthetic lineages.