DNA Array Analysis of Changes in Preovulatory Gene Expression in the Rat Ovary1

Abstract

During the periovulatory period, the mammalian ovary is the site of dramatic functional and structural changes, leading to oocyte maturation, follicle rupture, and corpus luteum formation. To a large extent, these processes result from changes in the transcriptome of various ovarian cell types. To develop a broader view of periovulatory changes in gene expression in the ovary and to identify further genes involved in periovulatory events, we used the recently developed DNA array technology. Immature female eCG-primed rats were killed either immediately before or 6 h after ovulation induction with hCG. Total ovarian RNA was isolated and used to prepare radiolabeled cDNA probes, which were hybridized to DNA arrays representing approximately 600 rat genes. Quantitative analysis identified a multitude of regulated gene messages, including several genes involved in extracellular matrix degradation and lipid/steroid metabolism previously reported to be induced by hCG. This screening also identified a group of candidate genes whose ovarian expression and gonadotropin regulation was hitherto unknown. The induction of three of these genes, encoding cutaneous fatty acid-binding protein, the interleukin-4 receptor alpha chain, and prepronociceptin, was confirmed and further characterized by Northern blot analysis. In addition, in situ hybridization analysis showed that hCG administration resulted in exclusive or predominant expression of all three genes in theca cells. These results demonstrate that DNA arrays can be used to identify genes regulated during the periovulatory period, thus contributing to a more detailed understanding of the molecular mechanisms of ovulation.

Ovulation-selective genes: the generation and characterization of an ovulatory-selective cDNA library

“…Even though the exact role of these genes in the ovulatory process is not clear yet, their diverse functions and spatial expression pattern in the ovary reaffirmed the complexity and global nature of the ovulatory process. Leo et al (2001), in turn, have used DNA microarray technology. cDNAs prepared from ovarian RNA of rats, before and 6 h after the ovulatory trigger, were hybridized to DNA microarrays representing 600 known rat genes.…”

Proteomic Analysis of the Mouse Ovary in Response to Two Gonadotropins, Follicle-Stimulating Hormone and Luteinizing Hormone

“…These complex biological processes in the ovary are accompanied by changes in the transcriptional and translational expressions of ovarian genes. Until now, to identify ovarian genes regulated by PMSG and/or hCG injection, a number of previous transcriptomic analyses using DNA microarrays have been performed [10,25,26]. Furthermore, a genome wide rat ovarian gene expression database (rOGED) has been constructed (http://web5.mccs.uky.edu/kolab/rogedendo.aspx) [27].…”

“…So far, a number of candidate genes with potential importance for ovarian functions have been identified by transcriptomic analysis [9][10][11][12]. One approach to investigating molecular events during the preovulatory and ovulatory phases is to reveal the gene expression profile of ovarian follicular cells by cDNA microarray in response to gonadotropin stimulation.…”

Molecular characterization and bioinformatics analysis of Ncoa7B, a novel ovulation-associated and reproduction system-specific Ncoa7 isoform

“…Genes known to be induced by LH during the ovulatory process include the progesterone receptor (PR; Park & Mayo 1991), cyclooxygenase-2 (COX2; Sirois & Richards 1992), CAAT-enhancer-binding protein b (CEBPB; Sirois & Richards 1993), early growth regulatory factor (Egr1; Espey et al 2000), pituitary adenylyl cyclase-activating peptide (PACAP; Park et al 2000), amphiregulin (Areg; Park et al 2004), receptor-interacting protein 140 (RIP140; Tullet et al 2005), hyaluronan synthase-2 (HAS2), tumor necrosis-stimulated gene-6 (TSG6; Richards 2005), endothelin-2 (EDN2; Ko et al 2006), estrogen sulfotransferase (EST; Gershon et al 2007), and other genes identified by microarray analysis (Leo et al 2001, Jo et al 2004, DD-RT-PCR (Espey & Richards 2002), and suppression subtractive hybridization (SSH; Hourvitz et al 2006, Gershon et al 2007. Some of the above-mentioned genes have been demonstrated as essential players in the ovulatory cascade, whereas the role of other genes, the expression of which is up-regulated following the LH surge, awaits further investigation.…”