Sam68 Regulates a Set of Alternatively Spliced Exons during Neurogenesis
Sam68 Regulates a Set of Alternatively Spliced Exons during Neurogenesis
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DOI：
10.1128/mcb.01349-08
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发表时间：
2009-01-01
影响因子：
5.3
通讯作者：
Black, Douglas L.
中科院分区：
文献类型：
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作者：
Chawla, Geetanjali;Lin, Chia-Ho;Black, Douglas L.
Sam 68（Src-associated in mitosis，68 kDa）是一种KH结构域RNA结合蛋白，参与多种细胞过程，包括前体mRNA的选择性剪接，但其功能尚不清楚。使用RNA干扰敲低Sam 68表达和剪接敏感的微阵列，我们确定了一组替代外显子的剪接依赖于Sam 68。一个新发现的靶外显子在β-肌聚糖（Sgce）的详细分析表明，两个RNA元件分布在相邻的内含子和RNA结合活性的Sam 68是必要的抑制Sgce外显子。Sam 68蛋白在P19细胞的神经元分化后上调，并且许多Sam 68 RNA靶标在此过程中的表达和剪接发生变化。当Sam 68被短发夹RNA敲低时，许多依赖Sam 68的剪接变化不会发生，P19细胞无法分化。我们还发现，从胚胎小鼠新皮层的原代神经元祖细胞的分化受到抑制的Sam 68耗尽和促进Sam 68过表达。因此，Sam 68通过其对一组特定的RNA靶标的作用来控制神经发生。
Sam68 (Src-associated in mitosis, 68 kDa) is a KH domain RNA binding protein implicated in a variety of cellular processes, including alternative pre-mRNA splicing, but its functions are not well understood. Using RNA interference knockdown of Sam68 expression and splicing-sensitive microarrays, we identified a set of alternative exons whose splicing depends on Sam68. Detailed analysis of one newly identified target exon in epsilon sarcoglycan (Sgce) showed that both RNA elements distributed across the adjacent introns and the RNA binding activity of Sam68 are necessary to repress the Sgce exon. Sam68 protein is upregulated upon neuronal differentiation of P19 cells, and many Sam68 RNA targets change in expression and splicing during this process. When Sam68 is knocked down by short hairpin RNAs, many Sam68-dependent splicing changes do not occur and P19 cells fail to differentiate. We also found that the differentiation of primary neuronal progenitor cells from embryonic mouse neocortex is suppressed by Sam68 depletion and promoted by Sam68 overexpression. Thus, Sam68 controls neurogenesis through its effects on a specific set of RNA targets.