He Pei-Jian, Hirata Masami, Yamauchi Nobuhiko, Hashimoto Seiichi, Hattori Masa-Aki
Laboratory of Reproductive Physiology and Biotechnology, Department of Animal and Marine Bioresource Sciences, Graduate School of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
J Endocrinol. 2007 Jun;193(3):413-20. doi: 10.1677/JOE-07-0044.
The circadian clock, regulating hormonal secretion and metabolisms in accordance with the environmental light-dark cycle, resides in almost all peripheral tissues as well as in the superchiasmatic nucleus. Clock gene expression has been found to be noncyclic during spermatogenesis and the differentiation of thymocytes. However, currently little is known about how cell differentiation could affect circadian clockwork. We performed this study using the in vitro real-time oscillation monitoring system to examine the clockwork in several types of differentiating cells originated from reproductive tissues of transgenic rats (constructed with Period gene 2 (Per2) promoter-destabilized luciferase reporter gene). After treatment with dexamethasone (DXM), persistent oscillation of Per2 expression was observed in both gonadotropin-induced and pregnant ovarian luteal cells, proliferative uterine stromal cells (USCs), and nondifferentiating testicular interstitial cells, with a cyclic period of ~24 h. In contrast to these cell types, only one cycle of oscillation was sustained in granulosa cells undergoing differentiation. Additionally, Per2 oscillation was irregular in USCs undergoing decidualization induced by medroxyprogesterone acetate plus N6, 2-O-dibutyryl adenosine 3':5'-cyclic monophosphate. Furthermore, no oscillation of Per2 expression was evoked by DXM in Leydig cells and thymocytes. In conclusion, the present study characterized the oscillation of Per2 gene expression in several types of ovarian, uterine, and testicular cells, and it is strongly suggested that circadian clockwork is affected during cellular differentiation.
生物钟根据环境明暗周期调节激素分泌和新陈代谢，存在于几乎所有外周组织以及视交叉上核中。研究发现，在精子发生和胸腺细胞分化过程中，生物钟基因表达是非周期性的。然而，目前对于细胞分化如何影响生物钟机制知之甚少。我们使用体外实时振荡监测系统进行了这项研究，以检测源自转基因大鼠生殖组织（构建有周期基因2（Per2）启动子 - 不稳定荧光素酶报告基因）的几种分化细胞中的生物钟机制。用地塞米松（DXM）处理后，在促性腺激素诱导的和妊娠的卵巢黄体细胞、增殖性子宫基质细胞（USCs）以及未分化的睾丸间质细胞中均观察到Per2表达的持续振荡，周期约为24小时。与这些细胞类型不同，正在分化的颗粒细胞中仅维持了一个振荡周期。此外，在醋酸甲羟孕酮加N6,2 - O - 二丁酰腺苷3':5'-环磷酸酯诱导蜕膜化的USCs中，Per2振荡是不规则的。此外，DXM在睾丸间质细胞和胸腺细胞中未引起Per2表达的振荡。总之，本研究对几种卵巢、子宫和睾丸细胞中Per2基因表达的振荡进行了表征，强烈提示在细胞分化过程中生物钟机制受到影响。
