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Vertebrate reproductive science and technology
RESEARCH ARTICLE

Expression profiles of select genes in cumulus–oocyte complexes from young and aged mares

Lindsay Cox A , Dirk K. Vanderwall A B , Kate C. Parkinson A , Alexis Sweat A and S. Clay Isom A
+ Author Affiliations
- Author Affiliations

A Department of Animal, Dairy and Veterinary Sciences, 4815 Old Main Hill, Utah State University, Logan, UT 84322-4815, USA.

B Corresponding author. Email: dirk.vanderwall@usu.edu

Reproduction, Fertility and Development 27(6) 914-924 https://doi.org/10.1071/RD14446
Submitted: 16 November 2014  Accepted: 17 April 2015   Published: 15 May 2015

Abstract

There is compelling evidence that oocytes from mares >18 years of age have a high incidence of inherent defects that result in early embryonic loss. In women, an age-related decrease in oocyte quality is associated with an increased incidence of aneuploidy and it has recently been determined that the gene expression profile of human oocytes is altered with advancing age. We hypothesised that similar age-related aberrations in gene expression occur in equine oocytes. Therefore, the aim of the present study was to compare gene expression profiles of individual oocytes and cumulus cells from young and aged mares, specifically evaluating genes that have been identified as being differentially expressed with advancing maternal age and/or aneuploidy in human oocytes. Expression of 48 genes was compared between 14 cumulus–oocyte complexes (COCs) from mares aged 3–12 years and 10 COCs from mares ≥18 years of age. Three genes (mitochondrial translational initiation factor 3 (IF3), heat shock transcription factor 5 (HSF5) and Y box binding protein 2 (YBX2)) were differentially expressed in oocytes, with all being more abundant in oocytes from young mares. Three genes (ADP-ribosylation factor-like 6 interacting protein 6 (ARL6IP6), BCL2-associated X protein (BAX) and hypoxia upregulated 1 (HYOU1)) were differentially expressed in cumulus cells, with all being more abundant in aged mares. The results of the present study confirm there are age-related differences in gene expression in equine COCs, which may be associated with the lower quality and decreased developmental competence of oocytes from aged mares.

Additional keyword: equine.


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