Supplementary Material for: The Glucocorticoid-Induced Leucine Zipper (GILZ) Is Essential for Spermatogonial Survival and Spermatogenesis

Spermatogenesis relies on the precise regulation of the self-renewal and differentiation of spermatogonia to provide a continuous supply of differentiating germ cells. The understanding of the cellular pathways regulating this equilibrium remains unfortunately incomplete. This investigation aimed to elucidate the testicular and ovarian functions of the glucocorticoid-induced leucine zipper protein (GILZ) encoded by the X-linked Tsc22d3 (Gilz) gene. We found that GILZ is specifically expressed in the cytoplasm of proliferating spermatogonia and preleptotene spermatocytes. While Gilz mutant female mice were fully fertile, constitutive or male germ cell-specific ablation of Gilz led to sterility due to a complete absence of post-meiotic germ cells and mature spermatozoa. Alterations were observed as early as postnatal day 5 during the first spermatogenic wave and included extensive apoptosis at the spermatogonial level and meiotic arrest in the mid-late zygotene stage. Overall, these data emphasize the essential role played by GILZ in mediating spermatogonial survival and spermatogenesis.精子发生（Spermatogenesis）依赖于对精原细胞（spermatogonia）自我更新与分化的精准调控，以持续提供可分化的生殖细胞（germ cells）。遗憾的是，目前学界对调控这一动态平衡的细胞通路仍未完全阐明。本研究旨在解析由X连锁Tsc22d3（Gilz）基因编码的糖皮质激素诱导亮氨酸拉链蛋白（GILZ）在睾丸与卵巢中的功能。我们发现，GILZ特异性表达于增殖型精原细胞及细线前期精母细胞（preleptotene spermatocytes）的细胞质中。尽管Gilz突变雌性小鼠可正常生育，但全身性或雄性生殖细胞特异性敲除Gilz会导致雄性不育，其原因是减数分裂后生殖细胞与成熟精子（mature spermatozoa）完全缺失。早在出生后第5天的第一次精子发生波中即可观察到异常：精原细胞层面出现大量细胞凋亡（apoptosis），且减数分裂阻滞（meiotic arrest）于合线期中后期。综上，本研究数据证实了GILZ在维持精原细胞存活及精子发生过程中的关键作用。