Exon-centric regulation of pyruvate kinase M alternative splicing via mutually exclusive exons.
Exon-centric regulation of pyruvate kinase M alternative splicing via mutually exclusive exons.
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DOI：
10.1093/jmcb/mjr030
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发表时间：
2012-04
影响因子：
5.5
通讯作者：
Zhenxun Wang;D. Chatterjee;H. Y. Jeon;Martin Akerman;M. V. Vander Heiden;L. Cantley;A. Krainer
中科院分区：
文献类型：
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作者：
Zhenxun Wang;D. Chatterjee;H. Y. Jeon;Martin Akerman;M. V. Vander Heiden;L. Cantley;A. Krainer
丙酮酸激酶 M 基因 (PK-M) 的选择性剪接可产生 M2 同工型并促进有氧糖酵解和肿瘤生长。然而，PK-M 的癌症特异性选择性剪接调节尚不完全清楚。在这里，我们证明 PK-M 通过对相互排斥的外显子 9 和 10 的相互作用进行调节，从而在癌细胞中外显子 9 被抑制，外显子 10 被激活。引人注目的是，外显子而非内含子顺式元件是 PK-M 剪接异构体比率的关键决定因素。使用系统的亚外显子重复方法，我们在外显子 10 中鉴定出一个有效的外显子剪接增强子，它与外显子 9 中的同源对应物仅相差两个核苷酸。我们将 SRSF3 确定为同源因子之一，并表明这种富含丝氨酸/精氨酸的蛋白质激活外显子 10 并介导葡萄糖代谢的变化。这些发现为瓦尔堡效应关键调节因子的选择性剪接的复杂调节提供了机制上的见解，并且对具有类似选择性剪接模式的其他基因也具有影响。
Alternative splicing of the pyruvate kinase M gene (PK-M) can generate the M2 isoform and promote aerobic glycolysis and tumor growth. However, the cancer-specific alternative splicing regulation of PK-M is not completely understood. Here, we demonstrate that PK-M is regulated by reciprocal effects on the mutually exclusive exons 9 and 10, such that exon 9 is repressed and exon 10 is activated in cancer cells. Strikingly, exonic, rather than intronic, cis-elements are key determinants of PK-M splicing isoform ratios. Using a systematic sub-exonic duplication approach, we identify a potent exonic splicing enhancer in exon 10, which differs from its homologous counterpart in exon 9 by only two nucleotides. We identify SRSF3 as one of the cognate factors, and show that this serine/arginine-rich protein activates exon 10 and mediates changes in glucose metabolism. These findings provide mechanistic insights into the complex regulation of alternative splicing of a key regulator of the Warburg effect, and also have implications for other genes with a similar pattern of alternative splicing.