Karman Bethany N, Tischkau Shelley A
Department of Veterinary Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA.
Biol Reprod. 2006 Oct;75(4):624-32. doi: 10.1095/biolreprod.106.050732. Epub 2006 Jun 28.
A molecular device that measures time on a daily, or circadian, scale is a nearly ubiquitous feature of eukaryotic organisms. A core group of clock genes, whose coordinated function is required for this timekeeping, is expressed both in the central clock and within numerous peripheral organs. We examined expression of clock genes in the rat ovary. Transcripts for core oscillator elements (Arntl, Clock, Per1, Per2, and Cry1) were present in the ovary as indicated by quantitative real-time RT-PCR. Rhythmic expression patterns of Arntl and Per2 transcripts and protein products were out of phase with respect to the central oscillator and in complete antiphase to each other. Expression of Arntl was significantly elevated after the LH surge on the day of proestrus. Finally, hCG treatment induced cyclic expression of both Arntl and Per2 gene products in hypophysectomized, immature rats primed with eCG. Collectively, these data suggest that the core underpinnings of the transcriptional/translational feedback loop that drives circadian rhythmicity is present in the rat ovary. Furthermore, the study identifies LH as a potential regulator of circadian clock gene rhythms in the ovary.
一种以每日或昼夜节律为时间尺度进行计时的分子装置，几乎是真核生物普遍具有的特征。一组核心时钟基因对于这种计时功能是必需的，它们的协同作用在中央时钟以及众多外周器官中均有表达。我们检测了大鼠卵巢中时钟基因的表达情况。通过定量实时逆转录聚合酶链反应（qRT-PCR）表明，卵巢中存在核心振荡器元件（芳香烃受体核转运蛋白样蛋白1（Arntl）、生物钟基因（Clock）、周期蛋白1（Per1）、周期蛋白2（Per2）和隐花色素1（Cry1））的转录本。Arntl和Per2转录本及蛋白质产物的节律性表达模式与中央振荡器不同步，且彼此完全反相。在动情前期促黄体生成素（LH）高峰后，Arntl的表达显著升高。最后，人绒毛膜促性腺激素（hCG）处理诱导了在经马绒毛膜促性腺激素（eCG）预处理的去垂体未成熟大鼠中Arntl和Per2基因产物的周期性表达。总体而言，这些数据表明，驱动昼夜节律性的转录/翻译反馈环的核心基础存在于大鼠卵巢中。此外，但该研究将LH确定为卵巢中昼夜节律时钟基因节律的潜在调节因子。
