Yoshida Mayumi, Kataoka Naoyuki, Miyauchi Kenjyo, Ohe Kenji, Iida Kei, Yoshida Suguru, Nojima Takayuki, Okuno Yukiko, Onogi Hiroshi, Usui Tomomi, Takeuchi Akihide, Hosoya Takamitsu, Suzuki Tsutomu, Hagiwara Masatoshi
Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan;
Laboratory for Malignancy Control Research, Medical Innovation Center, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan;
Proc Natl Acad Sci U S A. 2015 Mar 3;112(9):2764-9. doi: 10.1073/pnas.1415525112. Epub 2015 Feb 9.
Familial dysautonomia (FD), a hereditary sensory and autonomic neuropathy, is caused by missplicing of exon 20, resulting from an intronic mutation in the inhibitor of kappa light polypeptide gene enhancer in B cells, kinase complex-associated protein (IKBKAP) gene encoding IKK complex-associated protein (IKAP)/elongator protein 1 (ELP1). A newly established splicing reporter assay allowed us to visualize pathogenic splicing in cells and to screen small chemicals for the ability to correct the aberrant splicing of IKBKAP. Using this splicing reporter, we screened our chemical libraries and identified a compound, rectifier of aberrant splicing (RECTAS), that rectifies the aberrant IKBKAP splicing in cells from patients with FD. Here, we found that the levels of modified uridine at the wobble position in cytoplasmic tRNAs are reduced in cells from patients with FD and that treatment with RECTAS increases the expression of IKAP and recovers the tRNA modifications. These findings suggest that the missplicing of IKBKAP results in reduced tRNA modifications in patients with FD and that RECTAS is a promising therapeutic drug candidate for FD.
家族性自主神经功能障碍（FD）是一种遗传性感觉和自主神经病变，由20号外显子的剪接错误引起，该错误源于B细胞中κ轻链多肽基因增强子抑制剂、激酶复合物相关蛋白（IKBKAP）基因（编码IKK复合物相关蛋白（IKAP）/延伸因子1（ELP1））的内含子突变。一种新建立的剪接报告基因检测方法使我们能够在细胞中观察到致病性剪接，并筛选能够纠正IKBKAP异常剪接的小分子化合物。利用这种剪接报告基因，我们筛选了化学文库，鉴定出一种化合物——异常剪接矫正剂（RECTAS），它能纠正FD患者细胞中IKBKAP的异常剪接。在此，我们发现FD患者细胞中细胞质tRNA摆动位置的修饰尿苷水平降低，而RECTAS处理可增加IKAP的表达并恢复tRNA修饰。这些发现表明，IKBKAP的异常剪接导致FD患者tRNA修饰减少，并且RECTAS是一种有前景的FD治疗候选药物。
