School of Clinical Sciences, University of Bristol, Bristol BS1 3NY, United Kingdom, Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, São Paulo 14801-385, Brazil, School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom, and Department of Physiology, University of Malaya, Kuala Lumpur 50603, Malaysia.
J Neurosci. 2014 Mar 12;34(11):3810-20. doi: 10.1523/JNEUROSCI.4343-13.2014.
Arginine vasopressin (AVP) is a neurohypophysial hormone regulating hydromineral homeostasis. Here we show that the mRNA encoding cAMP responsive element-binding protein-3 like-1 (CREB3L1), a transcription factor of the CREB/activating transcription factor (ATF) family, increases in expression in parallel with AVP expression in supraoptic nuclei (SONs) and paraventicular nuclei (PVNs) of dehydrated (DH) and salt-loaded (SL) rats, compared with euhydrated (EH) controls. In EH animals, CREB3L1 protein is expressed in glial cells, but only at a low level in SON and PVN neurons, whereas robust upregulation in AVP neurons accompanied DH and SL rats. Concomitantly, CREB3L1 is activated by cleavage, with the N-terminal domain translocating from the Golgi, via the cytosol, to the nucleus. We also show that CREB3L1 mRNA levels correlate with AVP transcription level in SONs and PVNs following sodium depletion, and as a consequence of diurnal rhythm in the suprachiasmatic nucleus. We tested the hypothesis that CREB3L1 activates AVP gene transcription. Both full-length and constitutively active forms of CREB3L1 (CREB3L1CA) induce the expression of rat AVP promoter-luciferase reporter constructs, whereas a dominant-negative mutant reduces expression. Rat AVP promoter deletion constructs revealed that CRE-like and G-box sequences in the region between -170 and -120 bp are important for CREB3L1 actions. Direct binding of CREB3L1 to the AVP promoter was shown by chromatin immunoprecipitation both in vitro and in the SON itself. Injection of a lentiviral vector expressing CREB3L1CA into rat SONs and PVNs resulted in increased AVP biosynthesis. We thus identify CREB3L1 as a regulator of AVP transcription in the rat hypothalamus.
精氨酸加压素（AVP）是一种神经垂体激素，调节水盐平衡。在这里，我们发现 cAMP 反应元件结合蛋白-3 样-1（CREB3L1）的 mRNA 表达在脱水（DH）和盐负荷（SL）大鼠的视上核（SON）和室旁核（PVN）中与 AVP 表达平行增加，与正常水合（EH）对照组相比。在 EH 动物中，CREB3L1 蛋白在神经胶质细胞中表达，但在 SON 和 PVN 神经元中仅低水平表达，而在 DH 和 SL 大鼠中则强烈上调。同时，CREB3L1 通过切割激活，其 N 端结构域从高尔基体通过细胞质易位到细胞核。我们还表明，在 SON 和 PVN 中，CREB3L1 mRNA 水平与 AVP 转录水平相关，在钠耗竭后以及在视交叉上核的昼夜节律的影响下。我们测试了 CREB3L1 激活 AVP 基因转录的假设。全长和组成型激活形式的 CREB3L1（CREB3L1CA）诱导大鼠 AVP 启动子 - 荧光素酶报告基因构建体的表达，而显性负突变体降低表达。大鼠 AVP 启动子缺失构建体表明，在 -170 至 -120 bp 之间的区域中的 CRE 样和 G 盒序列对于 CREB3L1 作用很重要。染色质免疫沉淀实验表明，在体外和 SON 本身中均显示 CREB3L1 直接结合 AVP 启动子。将表达 CREB3L1CA 的慢病毒载体注射到大鼠 SON 和 PVN 中，导致 AVP 生物合成增加。因此，我们确定 CREB3L1 是大鼠下丘脑 AVP 转录的调节剂。
