STAR family RNA-binding protein ASD-2 regulates developmental switching of mutually exclusive alternative splicing in vivo
STAR family RNA-binding protein ASD-2 regulates developmental switching of mutually exclusive alternative splicing in vivo
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DOI：
10.1101/gad.1620608
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发表时间：
2008-02-01
影响因子：
10.5
通讯作者：
Kuroyanagi, Hidehito
中科院分区：
文献类型：
--
作者：
Ohno, Genta;Hagiwara, Masatoshi;Kuroyanagi, Hidehito
前mRNAs的选择性剪接极大地促进了后生动物基因表达的时空多样性。然而，发育调控的分子基础和体内替代的前mRNA处理的准确序列还知之甚少。在本研究中，我们重点研究了秀丽线虫let-2基因从胚胎的外显子9到成虫的外显子10的互斥选择性剪接的发育转换。通过绿色荧光蛋白(GFP)和红色荧光蛋白(RFP)的差异表达来可视化let-2互斥外显子的使用，我们分离了几个开关缺陷突变株，并鉴定了选择性剪接缺陷-2(ASD-2)基因，编码进化保守的STAR(信号转导激活因子of RNA)RNA结合蛋白家族的一个新成员。比较同步野生型和asd-2突变虫体中部分剪接的let-2 RNA的数量表明，let-2互斥外显子下游的任一内含子在上游外显子被移除之前被移除，而ASD-2在幼虫后期促进内含子10的有偏切割。我们认为，不同内含子去除序列之间的发育切换决定了成熟let-2mRNA异构体之间的比例。
Alternative splicing of pre-mRNAs greatly contributes to the spatiotemporal diversity of gene expression in metazoans. However, the molecular basis of developmental regulation and the precise sequence of alternative pre-mRNA processing in vivo are poorly understood. In the present study, we focus on the developmental switching of the mutually exclusive alternative splicing of the let-2 gene of Caenorhabditis elegans from the exon 9 form in embryos to the exon 10 form in adults. By visualizing the usage of the let-2 mutually exclusive exons through differential expression of green fluorescent protein (GFP) and red fluorescent protein (RFP), we isolated several switching-defective mutants and identified the alternative splicing defective-2 (asd-2) gene, encoding a novel member of the evolutionarily conserved STAR (signal transduction activators of RNA) family of RNA-binding proteins. Comparison of the amounts of partially spliced let-2 RNAs in synchronized wild-type and asd-2 mutant worms suggested that either of the introns downstream from the let-2 mutually exclusive exons is removed prior to the removal of the upstream ones, and that asd-2 promotes biased excision of intron 10 in the late larval stages. We propose that the developmental switching between alternative sequences of intron removal determines the ratio between the mature let-2 mRNA isoforms.