Identification of SNPs in Intron 3 of Osteopontin Gene in Egyptian Buffalo Bulls with High and Low Quality Semen

Abstract

T HIS study investigated the genetic polymorphism of osteopontin (OPN) gene in Egyptian buffalo bulls in a trial for association with the quality of fresh semen. A total of 228 fresh semen ejaculates were collected from 57 buffalo bulls. Checking the fertility potential, the ejaculates were evaluated for volume, individual motility, live sperm, sperm abnormalities and concentration. The bulls' semen was grouped according to the individual motility into high (>60%, n=47) and low (<60%, n=10) quality. A fragment of 250 bp from intron 3 of OPN gene was amplified by PCR then genotyped by restriction fragment length polymorphism, single strand conformation polymorphism and DNA sequencing. The high-quality semen was significantly increased in individual motility % (p<0.0001), live sperm % (p<0.0001) and sperm concentration (p<0.05) than the low quality. Also, the monomorphic pattern of OPN gene in both groups of bulls was noticed. However, five mutations were discovered including three nucleotide insertions (T 44, A49 and A62) and two nucleotide substitutions (G11>C and A108>G) when comparing the sequence with that of buffalo in the GenBank. In conclusion, OPN gene might have no genetic variation and so it is not associated with semen quality in Egyptian buffalo bulls. Future studies with a larger number of populations on different regions of OPN gene are recommended.

A Missense p.Q>R234 Mutation in the Osteopontin Gene Is Associated With the Prolificacy of Iraqi Awassi Ewes

“…Osteopontin plays a critical role in reproduction as a fertility protein. 12 During pregnancy, OPN/SPP1 is synthesized and secreted by the glandular epithelium of the uterus as well as the luminal epithelium, where it stimulates nutrient transit by binding to integrins, facilitating the transfer of nutrients from the chorionic membrane to the placental vasculature and allantoic cavity of the embryo/fetus. 37 By attaching to specific integrins, OPN facilitates trophectoderm differentiation and attachment to the uterine luminal epithelium, which may play a crucial role in conceptus expansion and implantation.…”

“… 11 Osteopontin is expressed initially in osteoblasts, as well as in ovarian follicles and ovaries, and in the myometrium and endometrium in the reproductive tissues. 12 Uterine epitheliums (glands and luminal) express this protein, which interacts with the embryo using integrins to promote adhesion and communication between the uterus and the developing embryos. 13 In particular, OPN is persistently expressed on the maternal-fetal interface, which suggests that OPN is also crucial for maintaining a microenvironment that promotes embryonic and placental development.…”