Dataset Information

Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation.

ABSTRACT: BACKGROUND: Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary during final ovarian maturation (FOM) and ovulation. METHODS: Female fish possessing late vitellogenic oocytes were injected with GnRH analogue to induce FOM and ovulation. Fish were observed for daily spawning activities and sampled one week post-injection at germinal vesicle migration (GVM), oocyte hydration, ovulation, and post-ovulatory time periods. Changes in relative mRNA levels of kiss and gnrh forms in the brain were determined using quantitative real-time PCR. Changes in GnRH peptides in the brain and pituitary were analyzed using time-resolved fluoroimmunoassay. RESULTS: Both kiss1 and kiss2 mRNA levels in the brain were low at late vitellogenic stage and increased significantly during the GVM period. However, kiss1 mRNA levels decreased during oocyte hydration before increasing again at ovulatory and post-ovulatory periods. In contrast, kiss2 mRNA levels decreased at ovulatory and post-ovulatory periods. Levels of gnrh1 mRNA in the brain increased only during post-ovulatory period. However, levels of gnrh2 and gnrh3 mRNAs were elevated during GVM and then, decreased during oocyte hydration before increasing again at ovulatory period. During post-ovulatory period, both gnrh2 and gnrh3 mRNA levels declined. Peptide levels of all three GnRH forms in the brain were elevated during GVM and oocyte hydration; their levels were significantly lower during late vitellogenic, ovulatory, and post-ovulatory periods. In contrast, pituitary GnRH peptide levels did not show any significant fluctuations, with the GnRH1 peptide levels being many-fold higher than the GnRH2 and GnRH3 forms. CONCLUSION: The results indicate increased expression of multiple Kiss and GnRH forms in the brain and suggest their possible involvement in the regulation of FOM and ovulation in captive female chub mackerel.

SUBMITTER: Selvaraj S

PROVIDER: S-EPMC3453514 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation.

Selvaraj Sethu S Kitano Hajime H Amano Masafumi M Ohga Hirofumi H Yoneda Michio M Yamaguchi Akihiko A Shimizu Akio A Matsuyama Michiya M

Reproductive biology and endocrinology : RB&E 20120827

<h4>Background</h4>Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary ...[more]

PMID: 22925208

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Project description:Purpose: The goal of this study was to identify differentially expressed genes and pathways between the cumulus of compact/unstimulated cumulus-oocyte-complex (COC) and the cumulus of expanded/stimulated COC. Methods: mRNA profiles of Compact/unstimulated cumulus cells (CCs) from germinal vesicle (GV) COC obtained from two patients undergoing unstimulated IVM procedure and expanded/stimulated CCs from metaphase 2 (MII) COC obtained from three patients undergoing IVF/ICSI were generated by deep sequencing using Illumina HiSeq 2000. The sequence reads that passed quality filters were mapped to the human genome (hg19) using Tophat software. Differential expression analysis was done using DESeq bioconductor package. qRT–PCR validation was performed using SYBR Green assays. Results: A total of 40-80 million sequence reads per sample were mapped to the human genome (hg19). A total of 1746 differentially expressed genes between compact and expanded CCs with fold change > 2, and adjusted p value < 0.05 were identified. Gene ontology analysis of differentially expressed genes revealed a number of cellular processes regulated during the periovulatory interval including cellular movement, inflammatory response, immune cell trafficking, tissue development, lipid metabolism, tissue morphology, DNA replication and cell cycle. A total of 116 of the differentially expressed genes were annotated as long non-coding RNAs, 10 of them coded from introns of genes known to be involved in granulosa cell processes suggesting that unique non coding RNA transcripts may contribute to the regulation of cumulus expansion and oocyte maturation. Results were validated using qRT-PCR. Conclusions: Using global transcriptome sequencing we identified new important genes and non coding RNAs involved in COC maturation and cumulus expansion, which may contribute to improve the process of in vitro maturation of immature oocytes utilized in IVM cycles mRNA profiles of Compact/unstimulated cumulus cells (CCs) from germinal vesicle (GV) COC obtained from two patients undergoing unstimulated IVM procedure and expanded/stimulated CCs from metaphase 2 (MII) COC obtained from three patients undergoing IVF/ICSI were generated by deep sequencing using Illumina HiSeq 2000.

Dataset Information

Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation.

Publications

Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation.

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