A model system for activation-induced alternative splicing of CD45 Pre-mRNA in T cells implicates protein kinase C and Ras
A model system for activation-induced alternative splicing of CD45 Pre-mRNA in T cells implicates protein kinase C and Ras
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DOI：
10.1128/mcb.20.1.70-80.2000
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发表时间：
2000-01-01
影响因子：
5.3
通讯作者：
Weiss, A
中科院分区：
文献类型：
--
作者：
Lynch, KW;Weiss, A
人类T细胞表面表达多种亚型的蛋白酪氨酸磷酸酶CD45。有趣的是，这些异构体的表达已经被证明在T细胞激活时显著不同。在这份报告中，我们描述了一种新的基于细胞系的模型系统，在该系统中，我们可以模拟在原始T细胞中观察到的激活诱导的CD45选择性剪接。在T细胞刺激诱导的许多近端信号事件中，我们发现蛋白激酶C的激活和RAS的激活对于CD45可变外显子的排除是重要的，而与钙离子流动相关的事件则不重要。此外，放线菌亚胺阻断CD45激活诱导的选择性剪接的能力表明需要从头合成蛋白质。我们进一步证明，以前涉及CD45可变外显子的组织特异性调控的序列对于激活诱导的剪接同样是必要的和充分的。这些结果初步了解了T细胞激活时CD45选择性剪接的要求，并证实了这种新的细胞系在促进对CD45激活诱导调控的更详细分析方面的重要性。
Multiple isoforms of the protein tyrosine phosphatase CD45 are expressed on the surface of human T cells. Interestingly, the expression of these isoforms has been shown to vary significantly upon T-cell activation. In this report, we describe a novel cell line-based model system in which we can mimic the activation-induced alternative splicing of CD45 observed in primary T cells. Of the many proximal signaling events induced by T-cell stimulation, we show that activation of protein kinase C and activation of Ras are important for the switch toward the exclusion of CD45 variable exons, whereas events related to Ca2+ flux are not. In addition, the ability of cycloheximide to block the activation-induced alternative splicing of CD45 suggests a requirement for de novo protein synthesis. We further demonstrate that sequences which have previously been implicated in the tissue-specific regulation of CD45 variable exons are likewise necessary and sufficient for activation-induced splicing. These results provide an initial understanding of the requirements for CD45 alternative splicing upon T-cell activation, and they confirm the importance of this novel cell line in facilitating a more detailed analysis of the activation-induced regulation of CD45 than has been previously possible.