Splintrons in Giardia intestinalis: Spliceosomal introns in a split form.
Splintrons in Giardia intestinalis: Spliceosomal introns in a split form.
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DOI：
10.4161/cib.4.4.15466
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发表时间：
2011-07-01
影响因子：
--
通讯作者：
Hashimoto, Tetsuo
中科院分区：
文献类型：
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作者：
Kamikawa, Ryoma;Inagaki, Yuji;Hashimoto, Tetsuo
分歧真核单细胞生物贾第鞭毛虫是人类和各种动物的肠道寄生虫。对基因组序列草图的分析表明，G.大肠杆菌具有比其他模式真核生物（例如，拟南芥和人）。这是G.迄今为止，在这种生物体中只发现了四个剪接体（顺式剪接）内含子，这一事实似乎与拟南芥基因组一致。我们最近证明了G.大肠杆菌具有独特的基因表达系统，包括剪接体介导的反式剪接。G.在基因组中，基因组被分成多个片段，每个基因片段独立转录。两个特定的前mRNA通过形成分子间茎结构直接相互作用，然后通过剪接体反式剪接成成熟的mRNA。我们认为，这种反式剪接其次是由切除典型（顺式剪接）内含子的系统引起的。基于这些发现，我们怀疑类似的现象-分裂基因和转录后组装的转录本通过反式剪接-可能是普遍存在于更不同的真核细胞谱系比以前已知的，特别是在生物体拥有“内含子贫困”的基因组。
The divergent eukaryotic unicellular organism Giardia intestinalis is an intestinal parasite in humans and various animals. An analysis of a draft genome sequence suggested that G. intestinalis has a much simpler genome organization and gene repertoire than those of other model eukaryotic organisms (e.g., Arabidopsis and human). This general picture of the G. intestinalis genome seemingly agrees with the fact that only four spliceosomal (cisspliced) introns have been identified in this organism to date. We have recently shown that G. intestinalis possesses a unique gene expression system incorporating spliceosome-mediated trans-splicing. Some protein-coding genes in G. intestinalis are split into multiple pieces in the genome and each gene fragment is independently transcribed. Two particular pre-mRNAs directly interact with each other by forming an intermolecularstem structure and are then trans-spliced into a mature mRNA by spliceosomes. We believe that this trans-splicing secondarily arose from the system that excises canonical (cis-splicing) introns. Based on these findings, we suspect that similar phenomena - split genes and post-transcriptional assemblage of their transcripts via trans-splicing - may be prevalent in more distinct eukaryotic lineages than previously known, particularly in organisms possessing "intronpoor" genomes.