The disruption of circadian clockwork in differentiating cells from rat reproductive tissues as identified by in vitro real-time monitoring system.
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.
He
Pei-Jian
PJ
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.
Hirata
Masami
M
Yamauchi
Nobuhiko
N
Hashimoto
Seiichi
S
Hattori
Masa-Aki
MA
D000818:Animals; D030801:Animals, Genetically Modified; D001683:Biological Clocks / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D003199:Computer Systems; D003338:Corpus Luteum / Q000166:cytology; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D056950:Period Circadian Proteins; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017154:Stromal Cells / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D014599:Uterus / Q000378:metabolism
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C513311:Per2 protein, rat; D056950:Period Circadian Proteins; D012333:RNA, Messenger