THE FUNCTIONAL ROLE OF PRAMEY IN SPERMIOGENESIS IN CATTLE

Decreased male fertility is a significant problem in cattle and other livestock species. To address this problem, we have studied the bovine male specific sex chromosome - Y chromosome, and identified a novel gene family, named preferentially expressed antigen in melanoma, Y-linked (PRAMEY). Copy number variation (CNV) of PRAMEY has been associated with bull testis size, semen quality and fertility traits. PRAMEY encodes a protein that is highly expressed in almost all types of cancer cells. However, among the non-tumor tissues, it is expressed in the testis only. PRAMEY is believed to play a role in reproduction and immune response. The molecular mechanism underlying the function of PRAMEY in reproduction is still unknown. We hypothesize that PRAMEY interacts with signaling molecules, including the protein phosphatase-1 gamma 2 (PP1γ2), and plays an essential role in sperm formation and sperm function. The objective of this project is to determine the role of PRAMEY in sperm formation through two specific aims: 1) to determine the role of PRAMEY in acrosome formation, and 2) to determine how PRAMEY regulates sperm function during fertilization. The outcomes of this project will provide fundamental knowledge of the role of the PRAMEY gene family during spermatogenesis and fertilization, and will help animal breeders to improve male fertility by identifying high-fertility bulls. This project is highly innovative, crucial and significant to our understanding of the molecular mechanism underlying sperm formation and sperm function. We believe that the outcome of this project has important implications for reproduction of cattle and other livestock mammals.