Tissue-specific mRNA expression profile of ESR2 gene in goat

Estimates show that in the world about 30 million goats and in Iran about five million Cashmere goat are bred. One of the most important of these breeds is the Raini Cashmere goat. Steroid hormones perform their physiological functions by regulating the transcription of target genes. Receptors for these hormones play a role in osteoporosis, inflammation and cancer through transcription networks. Estrogen receptor (ER) is a transcription factor that mediates the function of estrogen in many physiological and pathological processes. There are two estrogen receptors, ESR1 and ESR2, which are located in the reproductive organs. Reproduction rate, especially fertility, is one of the most important economic traits in animal production and is regulated by genetic and environmental factors. Therefore, the aim of this study was to investigate the expression profile of ESR2 gene in different tissues of fluffy goats using Real Time PCR.

Sampling of testis, ovarian, uterine, breast, brain, kidney and heart tissues was performed from a male and a female goat (3 replicates from each tissue). Total RNA was extracted from the tissues and the quality and quantity of the extracted RNA were evaluated. The cDNA was then synthesized and Real Time PCR was performed. The GAPDH housekeeping gene was used as a control. Melting curves were examined and data obtained from Real Time PCR were analyzed. 

The results of Real Time PCR curves and observation of electrophoresis of PCR products on 2% agarose gel showed that ESR2 gene was expressed in testis, ovary, uterine, breast, brain, kidney, and heart tissues. The highest level of expression was observed in the ovary and then the brain and uterus and the lowest level of expression was related to kidney, heart and testis tissues.

According to the results of the present research and the results of other studies, it can be concluded that ESR2 plays an important role in female fertility, because in the present study it was found that ESR2 is much more expressed in ovarian tissue than other tissues. Therefore, ESR2 is likely to be essential for female fertility, and the results of this study provide the basis for future research to describe the role of the ESR2 gene as a candidate gene for better fertility and normal physiology in domestic animals, especially goats.