Identification of developmental competence‐related genes in mature porcine oocytes

Abstract

Oocyte competence is a key factor limiting female fertility, yet the underlying molecular mechanisms that contribute to oocyte competence remain unclear. The objective of this study was to elucidate specific genes whose function contributes to oocyte competence. We observed that 6 of 20 target genes examined were differentially expressed between adult (more competent) and prepubertal (less competent) porcine in vitro matured (IVM) oocytes. These genes were the cholesterol synthesis related gene HMG-CoA reductase (HMGCR), fatty acid oxidation genes acyl-CoA synthetase long-chain family member 3 (ACSL3) and long-chain acyl-CoA dehydrogenase (ACADL), glycolytic genes fructose 1,6 bisphosphate aldolase (ALDOA) and lactate dehydrogenase C (LDHC), and tumor necrosis factor-α (TNF). These 6 genes, as well as 3 other genes (porcine endogenous retrovirus (PERV), transcribed loci 10 (TL10), serine/arginine-rich splicing factor 1 (SRSF1)), were further analyzed by comparing transcript abundance in IVM and in vivo matured (VVM) prepubertal and adult porcine oocytes. Among these 9 target genes, five were differentially expressed between IVM and VVM prepubertal oocytes, while eight genes were differentially expressed between IVM and VVM adult oocytes. None was differentially expressed between VVM prepubertal and adult oocytes. A functional study of TNF demonstrated that depletion of endogenous TNF decreased oocyte competence and TNFAIP6 expression in cumulus cells, while TNF in IVM medium regulated TNFAIP6 expression in cumulus cells. Differential expression of the genes identified in this study suggests that these genes may be functionally relevant to oocyte competence.

Enhanced fertility prediction of cryopreserved boar spermatozoa using novel sperm function assessment

“…In vitro fertilization using frozen-thawed boar spermatozoa achieved similar results to that of cooled boar semen used in our laboratory (Yuan et al, 2011;Silva et al, 2012;Yuan & Krisher, 2012). Although frozen-thawed spermatozoa are often used for IVF to improve the consistency and repeatability of experiments, we observed a considerable amount of variation unrelated to spermatozoa, similar to IVF results with cooled semen (Xu et al, 1996;Long et al, 1999;Gil et al, 2008).…”

Building a better mouse embryo assay: effects of mouse strain and in vitro maturation on sensitivity to contaminants of the culture environment

“…For relative quantification of gene expression, data were analyzed using the relative expression tool REST 2009 version 2.0.13 [34], as described previously [35,36]. Briefly, expression ratios were generated using PCR efficiencies of the target and reference genes and the ΔCT values of control blastocysts (0 % TX100) compared to blastocysts cultured in either low or high TX100.…”

Lipids and oocyte developmental competence: the role of fatty acids and β-oxidation

“…In rhesus monkey, microarray analysis found that several lipid metabolism genes, including some involved in b-oxidation, were dysregulated in cumulus cells R22 K R Dunning and others following IVM compared with those matured in vivo (Lee et al 2011). In porcine oocytes, levels of ACSL3 and ACADL, which activate long-chain fatty acids before their entry into mitochondria and catalyse the first step in the b-oxidation spiral respectively, were found to be dysregulated in another model of poor oocyte developmental competence (Yuan et al 2011). Recently we have found that mouse COCs matured in vitro metabolise fatty acid at less than half the rate of COCs matured in vivo, in association with dysregulated expression of at least 15 genes involved in fatty acid activation, transport and oxidation (Dunning et al 2014).…”