PRAMEY: A Bovid-Specific Y-Chromosome Multicopy Gene Is Highly Related to Postnatal Testicular Growth in Hu Sheep

Simple Summary PRAMEY (preferentially expressed antigen in melanoma, Y-linked) is a cancer-testis antigen and is believed to play an important role in testicular development and gametogenesis. However, the structure, expression and function of PRAMEY in sheep remain unknown. In this paper, we found that PRAMEY was extremely expressed in the testis and significantly upregulated during testicular growth. The mRNA abundance of PRAMEY was significantly correlated with testicular size traits in Hu sheep at 6 months. These results imply that PRAMEY may play an important role in testicular growth. PRAMEY (preferentially expressed antigen in melanoma, Y-linked) belongs to the cancer-testis antigens (CTAs) gene family and is predominantly expressed in testis, playing important roles in spermatogenesis and testicular development. This study cloned the full-length cDNA sequence of ovine PRAMEY using the rapid amplification of cDNA ends (RACE) method and analyzed the expression profile and copy number variation (CNV) of PRAMEY using quantitative real-time PCR (qPCR). The results revealed that the PRAMEY cDNA was 2099 bp in length with an open reading frame (ORF) of 1536 bp encoding 511 amino acids. PRAMEY was predominantly expressed in the testis and significantly upregulated during postnatal testicular development. The median copy number (MCN) of PRAMEY was 4, varying from 2 to 25 in 710 rams across eight sheep breeds. There was no significant correlation between the CNV of PRAMEY and testicular size, while a significant positive correlation was observed between the mRNA expression and testicular size in Hu sheep. The current study suggests that the expression levels of PRAMEY were closely associated with testicular size, indicating that PRAMEY may play an important role in testicular growth.