# PRAMEY enhances sperm-egg binding and modulates epigenetic dynamics in bovine embryogenesis

## TL;DR

This study shows that the PRAMEY gene in cattle affects sperm-egg binding and epigenetic changes during early embryo development.

## Contribution

The study reveals PRAMEY's role in enhancing sperm-egg binding and modulating DNA and histone methylation in bovine embryos.

## Key findings

- PRAMEY antibody treatment increased sperm binding per oocyte at all time points, especially at 6 hours post-fertilization.
- PRAMEY ab-treated spermatozoa reduced DNA methylation in paternal and maternal pronuclei at specific stages.
- H3K27me3 histone methylation was significantly lower in embryos from PRAMEY ab-treated spermatozoa at the 8-cell and morula stages.

## Abstract

Infertility and subfertility are significant reproductive challenges in cattle, often linked to genetic factors. Among these genetic factors, the bovine Y-linked gene family, PRAMEY, has emerged as a candidate due to its involvement in germ cell formation, fertilization, and embryonic development. This study investigates PRAMEY’s role in sperm-egg binding, acrosome integrity, and epigenetic modifications during fertilization and early embryogenesis. Using IVF with bovine spermatozoa treated with either PRAMEY antibody (ab) or rabbit IgG control, we assessed sperm-egg binding and acrosome integrity at 2, 4, and 6 h post-fertilization (hpf). PRAMEY ab treatment doubled sperm binding per oocyte across all time points, with a significant increase at 6 hpf (P ≤ 0.05), although no differences in acrosome integrity were observed (P > 0.05). To explore PRAMEY’s role in epigenetic regulation, we analyzed DNA (5-methylcytosine (5-mC)) and histone (H3K9me3 and H3K27me3) methylation in zygotes and embryos using immunofluorescent staining techniques. Zygotes derived from PRAMEY ab-treated spermatozoa showed significantly reduced DNA methylation in paternal pronuclei at 10 hpf and maternal pronuclei at 25 hpf (P ≤ 0.01). Histone methylation analysis revealed no significant differences in H3K9me3 methylation between groups, but H3K27me3 methylation was significantly lower in embryos produced using PRAMEY ab-treated spermatozoa at the 8-cell and morula stages (P ≤ 0.05). In summary, PRAMEY inhibition enhances sperm-egg binding and influences DNA and histone methylation dynamics in bovine embryos, underscoring its potential role in fertilization and early embryonic epigenetic regulation.

The online version contains supplementary material available at 10.1007/s00441-025-03975-1.