Histomorphological Comparisons and Expression Patterns of BOLL Gene in Sheep Testes at Different Development Stages

Boule homolog, RNA binding protein (BOLL), an ancestral member of the DAZ (deleted in azoospermia) gene family, is required for testicular function, maintenance, and spermatogenesis in males. However, in sheep, little is known about the expression profiles and molecular function of BOLL. In In this study, obvious seminiferous tubule lumens and various spermatogenic cells, including spermatogonia, primary and secondary spermatocytes, round spermatids, elongated spermatids, and spermatozoa, were observed in the testes of sheep aged 1 year and older. Our results showed that BOLL was expressed exclusively in sheep testes. Moreover, significant BOLL expression at the transcript and protein levels were discovered in 1- and 2-year-old sheep testes, in comparison with testes from 0-day-, 2-month-, and 5-month-old sheep. BOLL protein was located in spermatogenic cells, ranging from primary spermatocytes to round spermatids, as well as in spermatozoa with intensive immunoexpression. A preliminary study demonstrated that the sheep BOLL gene is critical for meiosis and sperm maturity. This study contributes to further understanding the regulatory mechanisms of the BOLL gene during spermatogenesis