PRM1 Gene Expression and Its Protein Abundance in Frozen-Thawed Spermatozoa as Potential Fertility Markers in Breeding Bulls

Abstract

Functional genes and proteins in sperm play an essential role in bulls’ reproductive processes. They are more accurate in determining bull fertility than conventional semen quality tests. Protamine-1 (PRM1) is a gene or protein crucial for packaging and protecting sperm DNA until fertilization affects normal sperm function. This study analyzes the genes and proteins potential from PRM1 as fertility markers for different breeds of bulls utilized in the artificial insemination programs, expected to be an accurate tool in interpreting bull fertility in Indonesia. This study used Limousin, Holstein, and Ongole Grade bulls divided into two groups based on fertility, high-fertility (HF) and low fertility (LF). The semen quality assessment included progressive motility (computer-assisted semen analysis), viability (eosin-nigrosine), and plasma membrane integrity (HOS test). Sperm DNA fragmentation (SDF) was assessed using the acridine orange staining and the Halomax test. Sperm PRM deficiency was evaluated with the chromomycin A3 method. Moreover, PRM1 gene expression was measured using qRT-PCR, and the PRM1 protein abundance was measured with the enzyme immunoassay method. Semen quality values, relative expression of PRM1 gene, and quantity of PRM1 protein were significantly higher (p < 0.05) in HF bulls than in LF bulls. The SDF and PRM deficiency values in LF bulls were significantly higher (p < 0.05) than HF bulls. Additionally, PRM1 at the gene and protein levels correlated significantly (p < 0.01) with fertility. Therefore, PRM1 is a potential candidate for fertility markers in bulls in Indonesia.

Differential Expressions of Protamine 1 (PRM1) and Protamine 2 (PRM2) Genes as Markers of Semen Quality in Pasundan Bulls

“…The mRNA level of the PRM2 gene in crossbred Frieswal cattle showed no difference between high-quality and low-quality sperms. The abundance of PRM1 gene in motile sperm by sperm fraction separation was detected in Bos indicus (Raval et al, 2019) and Bos taurus (Pardede et al, 2022). Other results were reported by Parthipan et al (2017) for Bos taurus that the PRM1 expression level showed no difference between high and low fertility groups.…”

“…A study on crossbred Frieswal cattle revealed a higher transcript level of PRM1 (p<0.05) in the group with high-quality sperm (progressive motility: 57.61±1.41%) than in the group with low-quality semen (progressive motility: 18.45±1.61%). The high mRNA expression of the PRM1 gene is due to its role in sperm DNA packaging and stabilization (Pardede et al, 2022). The mRNA level of the PRM2 gene in crossbred Frieswal cattle showed no difference between high-quality and low-quality sperms.…”

“…PRM1 abundance may be influenced by fertility status (Pardede et al, 2022). Different expression levels in PRM1 and PRM2 genes from the sperm mRNA occur in fertile and infertile males (Bansal et al, 2015).…”

Sperm Transcriptome Analysis Accurately Reveals Male Fertility Potential in Livestock

“…Many transcriptomic studies have been carried out on livestock related to reproductive phenotypes ( Table 2 ). A correlation between the semen and fertility marker genes has been found in bovine [ 23 , 26 , 36 , 54 , 58 , 60 , 61 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ], horses [ 25 , 28 , 77 ], buffalo [ 78 , 79 ], pig [ 56 , 64 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 ], goat [ 88 , 89 ], ram [ 90 , 91 , 92 , 93 ], and poultry [ 31 , 41 , 94 , 95 , 96 ]. The presence of RNA in sperm and semen can reflect the maturity level of sperm.…”

“…This indicates the impairment of protamine expressions can cause aberrant spermatogenesis. According to Pardede et al [ 70 ], PRM gene expression positively correlated with the conception rate in Limousin, Holstein, and Ongole Grade bulls. Their expression level was significantly higher in the high-fertility group.…”