Expression Analysis of IZUMO1 Gene during Testicular Development of Datong Yak (Bos Grunniens)

SIMPLE SUMMARY: IZUMO1 (IZUMO sperm-egg fusion) is a crucial member of the immunoglobulin superfamily, and it plays a vital part in egg sperm interaction, fusion, and in spermatogenesis. Previous studies identified the fundamental role of the IZUMO1 gene in meiosis of bovine spermatogenesis and spermatogenic cell development and fertility. The current study confirmed the significant expression of the IZUMO1 gene with testicular development and its potential role in fertilization of Datong yak. This research explained the biological role of IZUMO1 in yak reproduction; therefore in the future it might provide a novel prospect to apply data on reproduction and to understand the further regulatory mechanisms of the IZUMO1 gene during spermatogenesis of different mammalian species. ABSTRACT: The IZUMO1 gene has promising benefits for the national development of novel non-hormonal contraceptives and in the treatments of fertility. Understanding the function of IZUMO1, its mRNA, and protein expression is critical to gain insight into spermatogenesis and promote sperm-egg fusion during reproduction of Datong yak. Therefore, we estimated the IZUMO1 gene expression in different ages of Datong yak by using semi quantitative PCR, qPCR, and western blotting. The results of the qPCR, semi-quantitative PCR and western blotting revealed that the expression level of IZUMO1 mRNA was significantly (p < 0.05) higher in the testis of 30 months and 6 years old followed by 18 and 6 months old Datong yak, respectively. We also predicted secondary and tertiary protein structure of IZUMO1 by using bioinformatics software that the revealed presence of a signal peptide, Izumo domain, immunoglobulin (Ig) like domain, and transmembrane region. Moreover, immunostaining analysis also elucidated that IZUMO1 was more prominent in the testis of 30 months and 6 years old yak, which represented that the IZUMO1 gene expression might be higher during the peak breeding ages (6 to 7 years) of the yak, and play a potential role in spermatogenesis, fertility, and testicular development.