Post-transcriptional Repair of a Split Heat Shock Protein 90 Gene by mRNA trans-Splicing
Post-transcriptional Repair of a Split Heat Shock Protein 90 Gene by mRNA trans-Splicing
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DOI：
10.1074/jbc.c110.208389
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发表时间：
2011-03-04
影响因子：
4.8
通讯作者：
Tatu, Utpal
中科院分区：
文献类型：
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作者：
Nageshan, Rishi Kumar;Roy, Nainita;Tatu, Utpal
热休克蛋白90参与了真核生物中从蛋白质折叠、细胞周期、信号转导和发育到进化的各种生物学过程。它还重要地参与调节原生动物的生长，如盘基网柄菌、杜氏利什曼原虫、恶性疟原虫、克氏锥虫和伊氏锥虫。选择性抑制Hsp90也被探索为一种针对癌症、疟疾或锥虫病等重要人类疾病的干预策略。蓝氏贾第鞭毛虫是一种简单的人和动物原生动物寄生虫，在热带国家具有显著的发病率和死亡率，是引起腹泻病的重要原因。在这里，我们证明了兰氏革兰氏菌胞液热休克蛋白90(Glhsp90)在同一支架上被分成两个大小相似的片段，相隔777kb。对这种似乎是贾第鞭毛虫特有的独特排列感兴趣，我们研究了GlHsp90的生物合成。我们使用基因组测序来确认贾第鞭毛虫HSP90的分裂性质。然而，针对该肽产生的特异性抗体检测到一种质量约为80 kDa的产物，表明转录后挽救了基因组缺陷。我们证明了两个独立的Hsp90转录本在反式中连接到一个长时间成熟的mRNA的证据，可能是通过RNA剪接。剪接连接带有经典顺式剪接内含子的特征，表明常规的顺式剪接机制可能足以修复开放阅读框架。与剪接位点相邻的“内含子”区域中的互补26-NT序列可能有助于定位两个用于处理的前-mRNAs。这是第一个通过反式剪接来转录后挽救分裂基因的例子。
Heat shock protein 90 participates in diverse biological processes ranging from protein folding, cell cycle, signal transduction and development to evolution in all eukaryotes. It is also critically involved in regulating growth of protozoa such as Dictyostelium discoideum, Leishmania donovani, Plasmodium falciparum, Trypanosoma cruzi, and Trypanosoma evansi. Selective inhibition of Hsp90 has also been explored as an intervention strategy against important human diseases such as cancer, malaria, or trypanosomiasis. Giardia lamblia, a simple protozoan parasite of humans and animals, is an important cause of diarrheal disease with significant morbidity and some mortality in tropical countries. Here we show that the G. lamblia cytosolic hsp90 ( glhsp90) is split in two similar sized fragments located 777 kb apart on the same scaffold. Intrigued by this unique arrangement, which appears to be specific for the Giardiinae, we have investigated the biosynthesis of GlHsp90. We used genome sequencing to confirm the split nature of the giardial hsp90. However, a specific antibody raised against the peptide detected a product with a mass of about 80 kDa, suggesting a post-transcriptional rescue of the genomic defect. We show evidence for the joining of the two independent Hsp90 transcripts in-trans to one long mature mRNA presumably by RNA splicing. The splicing junction carries hallmarks of classical cis-spliced introns, suggesting that the regular cis-splicing machinery may be sufficient for repair of the open reading frame. A complementary 26-nt sequence in the "intron" regions adjacent to the splice sites may assist in positioning the two pre-mRNAs for processing. This is the first example of post-transcriptional rescue of a split gene by trans-splicing.