Spermatogonial differentiation is a key step in spermatogenesis, yet the transcriptional programs that control this process are not fully defined. E4f1 has been reported to be essential for embryonic development, mitochondrial function and spermatogonial stem cell (SSC) maintenance in mice. However, its function in spermatogonial differentiation and meiosis progression is unknown. The Cre-loxP system was used to delete E4f1 in differentiated spermatogonia and early meiotic spermatocytes. E4f1 knockout significantly affected the development of spermatogonia and spermatocytes. The mitochondria in the spermatogonia of the E4f1-cKO mice were morphologically abnormal, and apoptosis was elevated. The most advanced germ cells in the seminiferous tubules of E4f1-cKO mice were spermatocytes at the early pachytene stage. Single-cell transcriptome analysis revealed that loss of E4f1 suppressed the expression of transcriptional regulators related to SSC maintenance (e.g., Uchl1, Zbtb16, Lin28a), spermatogonial differentiation and meiotic entry (e.g., Dmrt1, Sohlh1, Stra8). Furthermore, CUT&Tag analysis of a HIS-Tag knock-in mouse line revealed that 237 genes were associated with E4F1, including Cks2 and Hmgb2, two previously identified genes related to meiosis progression. Our results suggest that E4f1 helps ensure normal spermatogonial differentiation by regulating the expression of key differentiation-associated genes. It may also influence the meiotic procession of spermatocytes, potentially through modulating the expression of downstream candidate target genes such as Cks2 and Hmgb2. These results establish a crucial role for the E4f1-dependent transcriptional program in spermatogonial differentiation and meiosis, although further validation is required to fully elucidate the underlying mechanisms involved.
Wang et al. (Tue,) studied this question.