Investigation of gene stability in equine luteal tissue during mid-diestrus phase and early pregnancy - Research Article.
Authors: Ramsaran Leah N, Byron Michael, Parry Stephen, Lection Jennine, Back Bradley, Grenier Jen, Cheong Soon Hon, Diel de Amorim Mariana
Journal: BMC veterinary research
Summary
# Editorial Summary When researchers use RT-qPCR to measure gene expression in equine reproductive tissues, they must normalise their data against reference genes—standardised genes whose expression remains stable across different conditions. Currently, equine reproduction studies predominantly rely on three reference genes (ACTB, GAPDH and B2M), yet emerging evidence suggests these genes fluctuate considerably depending on tissue type and physiological state, potentially compromising the reliability of findings. Ramsaran and colleagues investigated whether these conventional reference genes remained stably expressed in corpus luteum tissue collected from mid-diestrus mares during both pregnancy and non-pregnancy, employing three independent stability analysis software packages (GeNorm, NormFinder and BestKeeper) to validate their results. Contrary to their hypothesis, the traditionally used reference genes did not demonstrate the most stable expression patterns in luteal tissue across these reproductive states, suggesting that equine reproduction studies may require alternative or additional reference genes for accurate RT-qPCR normalisation. These findings have important implications for practitioners interpreting published research on equine reproductive endocrinology and for researchers designing future studies involving luteal tissue gene expression, as using inappropriate reference genes could lead to misinterpretation of results and flawed conclusions about progesterone production and early pregnancy maintenance.
Read the full abstract on PubMed
Practical Takeaways
- •When conducting RT-qPCR studies on equine reproductive tissue, validate reference gene stability for your specific experimental conditions rather than assuming ACTB, GAPDH or B2M are appropriate
- •Selection of reference genes should account for pregnancy status and estrous cycle phase to ensure accurate normalization of results
- •Consider using multiple stability analysis software tools to confirm reference gene suitability before conducting expensive or time-consuming molecular studies
Key Findings
- •Common reference genes (ACTB, GAPDH, B2M) showed variable expression stability in equine corpus luteum across pregnant and non-pregnant states
- •Three stability software analyses (GeNorm, NormFinder, BestKeeper) were used to evaluate gene expression stability in luteal tissue
- •Study challenges the assumption that widely-used reference genes maintain consistent expression across different physiological states in equine reproductive tissue