Cell-permeant caged InsP3 ester shows that Ca2+ spike frequency can optimize gene expression
Cell-permeant caged InsP3 ester shows that Ca2+ spike frequency can optimize gene expression
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DOI：
10.1038/31965
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发表时间：
1998-04-30
期刊：
影响因子：
64.8
通讯作者：
Tsien, RY
中科院分区：
文献类型：
--
作者：
Li, WH;Llopis, J;Tsien, RY
肌醇1,4,5-三磷酸（InsP(3)）从细胞内储存中释放钙，并引发胞质游离钙水平的复杂波动和振荡（1-5）。为了确定哪些长期反应是由InsP(3)和胞质游离钙的振荡控制的，在空间和时间控制下将外源性InsP(3)输送到未渗透细胞群体中是有用的。在这里，我们报告了15步合成膜渗透，笼状InsP(3)从肌醇衍生物。该衍生物扩散到完整的细胞中，并被水解以产生笼化的、代谢稳定的InsP(3)衍生物。后一种衍生物在细胞质中以数百微摩尔的浓度积累，而不激活InsP(3)受体。紫外线照射释放的InsP(3)类似物几乎与真实的InsP(3)一样有效，并产生胞质游离钙的峰值，并通过活化T细胞的核因子刺激基因表达（6,7）。同样总量的InsP(3)类似物在间隔1分钟的重复闪光中释放时，比间隔0.5分钟或大于或等于2分钟、作为单脉冲或作为缓慢持续的平台释放时激发更多的基因表达，因此，在给定量的InsP下，胞质游离钙水平以大致生理速率的振荡最大化基因表达(3)。
Inositol 1,4,5-trisphosphate (InsP(3)) releases calcium from intracellular stores and triggers complex waves and oscillations in levels of cytosolic free calcium(1-5). To determine which longer-term responses are controlled by oscillations in InsP(3) and cytosolic free calcium, it would be useful to deliver exogenous InsP(3), under spatial and temporal control, into populations of unpermeabilized cells. Here we report the 15-step synthesis of a membrane-permeant, caged InsP(3) derivative from myo-inositol. This derivative diffused into intact cells and was hydrolysed to produce a caged, metabolically stable InsP(3) derivative. This latter derivative accumulated in the cytosol at concentrations of hundreds of micromolar, without activating the InsP(3) receptor. Ultraviolet illumination uncaged an InsP(3) analogue nearly as potent as real InsP(3), and generated spikes of cytosolic free calcium, and stimulated gene expression via the nuclear factor of activated T cells(6,7). The same total amount of InsP(3) analogue elicited much more gene expression when released by repetitive flashes at 1-minute intervals than when released at 0.5- or greater than or equal to 2-minute intervals, as a single pulse, or as a slow sustained plateau, Thus, oscillations in cytosolic free calcium levels at roughly physiological rates maximize gene expression for a given amount of InsP(3).