Norwegian College of Fishery Science, The Arctic University of Norway, Tromsø, Norway.
Nofima, Tromsø, Norway.
Mol Reprod Dev. 2022 Oct;89(10):471-484. doi: 10.1002/mrd.23635. Epub 2022 Jul 13.
The germ cells are essential for sexual reproduction by giving rise to the gametes, but the importance of germ cells for gonadal somatic functions varies among vertebrates. The RNA-binding dead end (Dnd) protein is necessary for the specification and migration of primordial germ cells to the future reproductive organs. Here, we ablated the gametes in Atlantic salmon males and females by microinjecting dnd antisense gapmer oligonucleotides at the zygotic stage. Precocious maturation was induced in above 50% of both germ cell-depleted and intact fertile males, but not in females, by exposure to an off-season photoperiod regime. Sterile and fertile males showed similar body growth, but maturing fish tended to be heavier than their immature counterparts. Pituitary fshβ messenger RNA levels strongly increased in maturing sterile and fertile males concomitant with the upregulated expression of Sertoli and Leydig cell markers. Plasma concentrations of 11-ketotestosterone and testosterone in maturing sterile males were significantly higher than the basal levels in immature fish, but lower than those in maturing fertile males. The study demonstrates that germ cells are not a prerequisite for the activation of the brain-pituitary-gonad axis and sex steroidogenesis in Atlantic salmon males, but may be important for the maintenance of gonadal somatic functions.
生殖细胞对于有性生殖至关重要，因为它们产生配子，但生殖细胞对于性腺体功能的重要性在脊椎动物中有所不同。RNA 结合无终止（Dnd）蛋白对于原始生殖细胞的特化和迁移到未来的生殖器官是必需的。在这里，我们通过在受精卵阶段注射 dnd 反义 gapmer 寡核苷酸来耗尽大西洋鲑鱼的雄性和雌性配子。通过暴露于非季节性光周期制度，超过 50%的生殖细胞耗竭和完整的有生育能力的雄性都被诱导早熟，但雌性不会。不育和有生育能力的雄性表现出相似的身体生长，但成熟的鱼类往往比未成熟的鱼类更重。成熟的不育和有生育能力的雄性的垂体 fshβ 信使 RNA 水平强烈增加，伴随着 Sertoli 和 Leydig 细胞标记物的上调表达。成熟不育雄性的血浆 11-酮睾酮和睾酮浓度明显高于未成熟鱼类的基础水平，但低于成熟有生育能力的雄性。这项研究表明，生殖细胞不是大西洋鲑鱼雄性大脑-垂体-性腺轴和性激素生物合成激活的必要条件，但可能对维持性腺体功能很重要。
