Gene regulation via excitation and BDNF is mediated by induction and phosphorylation of the Etv1 transcription factor in cerebellar granule cells
Gene regulation via excitation and BDNF is mediated by induction and phosphorylation of the Etv1 transcription factor in cerebellar granule cells
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DOI：
10.1073/pnas.1206418109
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发表时间：
2012-05-29
影响因子：
11.1
通讯作者：
Nakanishi, Shigetada
中科院分区：
文献类型：
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作者：
Abe, Haruka;Okazawa, Makoto;Nakanishi, Shigetada
在成熟的出生后小脑颗粒细胞中，Etv1/Er81转录因子通过刺激AMPA和NMDA受体、电压依赖性Nav1.2 Na+通道和电压依赖性Ca2+通道的顺序活性依赖性机制诱导。然后Etv1上调了一系列参与小脑回路的成熟基因。在这个过程中，BDNF也被诱导并参与这些成熟基因的上调。使用颗粒细胞的培养物，我们解决了活动依赖性和BDNF信号传导机制如何收敛于代表性NR2C NMDA受体和Tiam 1成熟基因的调节。BDNF通过TrkB-Erk级联上调NR2C和Tiam 1基因，并且这种上调不仅通过抑制活性依赖性信号传导机制来阻断，而且通过用Etv1 siRNA抑制Etv1表达来阻断。重要的是，Etv 1在BDNF信号级联中被Erk 1/2选择性磷酸化，这种磷酸化的抑制消除了BDNF诱导的NR2C和Tiam 1基因的上调。结合MEK和Etv1突变的荧光素酶报告基因分析表明，ERK介导的磷酸化Etv1与NR2C启动子序列的Ets基序相互作用，并且Etv1的丝氨酸94和苏氨酸簇和丝氨酸（Thr139，Thr143和Ser146）的磷酸化对于BDNF介导的NR2C启动子活性的激活是必不可少的。这项研究表明，NR2C和Tiam1成熟基因协同控制的Etv1和其磷酸化的BDNF信号级联的活性依赖性诱导。
In maturing postnatal cerebellar granule cells, the Etv1/Er81 transcription factor is induced by sequential activity-dependent mechanisms through stimulation of AMPA and NMDA receptors, voltage-dependent Nav1.2 Na+ channels, and voltage-dependent Ca2+ channels. Etv1 then up-regulates a battery of maturation genes involved in the cerebellar circuitry. In this process, BDNF is also induced and participates in the up-regulation of these maturation genes. Using cultures of granule cells, we addressed how the activity-dependent and BDNF signaling mechanisms converge on the regulation of the representative NR2C NMDA receptor and Tiam1 maturation genes. BDNF up-regulated both the NR2C and Tiam1 genes via the TrkB-Erk cascade and this up-regulation was blocked not only by inhibition of the activity-dependent signaling mechanisms but also by suppression of Etv1 expression with Etv1 siRNA. Importantly, Etv1 was selectively phosphorylated by Erk1/2 in the BDNF signaling cascade, and the inhibition of this phosphorylation abrogated the BDNF-induced up-regulation of the NR2C and Tiam1 genes. The luciferase reporter assays in combination with mutations of MEK and Etv1 indicated that the Erk-mediated, phosphorylated Etv1 interacted with the Ets motifs of the NR2C promoter sequence and that phosphorylation at both serine 94 and a cluster of threonines and a serine (Thr139, Thr143, and Ser146) of Etv1 was indispensable for the BDNF-mediated activation of the NR2C promoter activity. This study demonstrates that the NR2C and Tiam1 maturation genes are synergistically controlled by the activity-dependent induction of Etv1 and its phosphorylation by the BDNF signaling cascade.