Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Germany.
Genome Biol Evol. 2017 Apr 1;9(4):855-868. doi: 10.1093/gbe/evx052.
RNA editing is a post-transcriptional process that modifies RNA molecules leading to transcript sequences that differ from their template DNA. A-to-I editing was found to be widely distributed in nuclear transcripts of metazoa, but was detected in fungi only recently in a study of the filamentous ascomycete Fusarium graminearum that revealed extensive A-to-I editing of mRNAs in sexual structures (fruiting bodies). Here, we searched for putative RNA editing events in RNA-seq data from Sordaria macrospora and Pyronema confluens, two distantly related filamentous ascomycetes, and in data from the Taphrinomycete Schizosaccharomyces pombe. Like F. graminearum, S. macrospora is a member of the Sordariomycetes, whereas P. confluens belongs to the early-diverging group of Pezizomycetes. We found extensive A-to-I editing in RNA-seq data from sexual mycelium from both filamentous ascomycetes, but not in vegetative structures. A-to-I editing was not detected in different stages of meiosis of S. pombe. A comparison of A-to-I editing in S. macrospora with F. graminearum and P. confluens, respectively, revealed little conservation of individual editing sites. An analysis of RNA-seq data from two sterile developmental mutants of S. macrospora showed that A-to-I editing is strongly reduced in these strains. Sequencing of cDNA fragments containing more than one editing site from P. confluens showed that at the beginning of sexual development, transcripts were incompletely edited or unedited, whereas in later stages transcripts were more extensively edited. Taken together, these data suggest that A-to-I RNA editing is an evolutionary conserved feature during fruiting body development in filamentous ascomycetes.
RNA 编辑是一种转录后过程，可修饰 RNA 分子，导致转录序列与其模板 DNA 不同。研究发现，A-to-I 编辑广泛分布于后生动物的核转录本中，但最近在丝状子囊菌禾谷镰刀菌的研究中仅在真菌中检测到 A-to-I 编辑，该研究揭示了性结构（子实体）中 mRNA 的广泛 A-to-I 编辑。在这里，我们在两个亲缘关系较远的丝状子囊菌 Sordaria macrospora 和 Pyronema confluens 的 RNA-seq 数据以及 Taphrinomycete Schizosaccharomyces pombe 的数据中搜索了可能的 RNA 编辑事件。与禾谷镰刀菌一样，S. macrospora 是 Sordariomycetes 的成员，而 P. confluens 属于早期分化的 Pezizomycetes 组。我们在来自两种丝状子囊菌的有性菌丝体的 RNA-seq 数据中发现了广泛的 A-to-I 编辑，但在营养结构中没有发现。在 S. pombe 的不同减数分裂阶段未检测到 A-to-I 编辑。S. macrospora 中的 A-to-I 编辑与禾谷镰刀菌和 P. confluens 分别进行比较，发现单个编辑位点的保守性很小。对 S. macrospora 两个不育发育突变体的 RNA-seq 数据的分析表明，这些菌株中的 A-to-I 编辑明显减少。对来自 P. confluens 的含有多个编辑位点的 cDNA 片段进行测序表明，在性发育的早期，转录物未完全编辑或未编辑，而在后期转录物则被更广泛地编辑。综上所述，这些数据表明，在丝状子囊菌的子实体发育过程中，A-to-I RNA 编辑是一种进化保守的特征。
