# Exploration of Novel Markers in Tan Sheep Spermatogenesis

## TL;DR

This study identifies new markers for germ cell development in Tan sheep, which could help improve reproductive efficiency in livestock farming.

## Contribution

The study discovers novel gene markers specific to spermatogonia, spermatocytes, and spermatozoa in Tan sheep.

## Key findings

- SMC3, G3BP1, and AKAP4 show age-related expression patterns in Tan sheep germ cells.
- SMC3 co-localizes with PLZF in spermatogonia, G3BP1 with SYCP2 in spermatocytes, and AKAP4 with PNA in spermatozoa.
- These findings provide evidence for novel markers in the spermatogenesis of Tan sheep.

## Abstract

During the reproductive process of Tan sheep, the normal development and functional realization of spermatogonia, spermatocytes, and spermatozoa are crucial for ensuring reproductive efficiency. In-depth research on the regulatory mechanisms underlying the development of Tan sheep germ cells represent a vital basis for improving reproductive performance. However, current studies on these germ cells are hampered by a paucity of available markers for identification and investigation, along with multiple limitations associated with the existing ones. The present study characterized the developmental dynamics of germ cells across different ages in Tan sheep and explored novel markers specific to ovine spermatogonia, spermatocytes, and spermatozoa.

In livestock farming, the reproductive function and breeding performance of Tan sheep are crucial for enhancing farming efficiency. Despite advances in research on sheep germ cells, studies on the identification of markers for spermatogonia, spermatocytes, and spermatozoa in Tan sheep remain limited and inadequate. In this study, Tan sheep were used as research subjects to investigate the morphological characteristics of testicular tissues, the developmental status of germ cells, and potential novel markers for spermatogonia, spermatocytes, and spermatozoa across different ages (0 days, 60 days, 180 days, and 365 days). Homology of the SMC3, G3BP1, and AKAP4 genes was analyzed via NCBI alignment. The localization and expression characteristics of these genes in the testis tissues of Tan sheep were investigated using HE staining, qPCR, and immunofluorescence double staining. The results showed that from 0 to 365 days of age, with increasing age, spermatogonia, spermatocytes, and spermatids exhibited an orderly distribution, and mature spermatozoa appeared in the tubular lumen, marking the initial establishment of the spermatogenic process. The homology of SMC3, G3BP1, and AKAP4 was 90%, 85%, and 81%. The mRNA levels of SMC3 and G3BP1 in the testes of 60-day-old Tan sheep were significantly increased, while AKAP4 expression showed a gradual increase with advancing age. SMC3 was co-localized with PLZF in undifferentiated spermatogonia, G3BP1 was co-expressed with SYCP2 in spermatocytes, and AKAP4 was co-expressed with PNA in spermatozoa. The findings of this study provide further supportive evidence for novel markers of spermatogonia, spermatocytes, and spermatozoa in Tan sheep.