Germ cell-specific genes play an important role in establishing the reproductive system in sexual organisms and have been used as valuable markers for studying gametogenesis and sex differentiation. Previously, we isolated a vasa transcript as a germ cell marker to trace the origin and migration of germ cells in the oriental river prawn Macrobrachium nipponense. Here, we identified a new germ cell-specific marker MnTdrd RNA and assessed its temporal and spatial expression during oogenesis and embryogenesis. MnTdrd transcripts were expressed in high abundance in unfertilized eggs and embryos at cleavage stage and then dropped significantly during late embryogenesis, suggesting that MnTdrd mRNA is maternally inherited. In situ hybridization of ovarian tissue showed that MnTdrd mRNA was initially present in the cytoplasm of previtellogenic oocyte and localized to the perinuclear region as the accumulation of yolk in vitellogenic oocyte. Whole-mount in situ hybridization of embryos showed that MnTdrd-positive signals were only localized in one blastomere until 16-cell stage. In the blastula, there were approximately 16 MnTdrd-positive blastomeres. During embryonized-zoea stage, the MnTdrd-positive cells aggregated as a cluster and migrated to the genital rudiment which would develop into primordial germ cells (PGCs). The localized expression pattern of MnTdrd transcripts resembled that of the previously identified germ cell marker vasa, supporting the preformation mode of germ cell specification. Therefore, we concluded that MnTdrd, together with vasa, is a component of the germ plasm and might have critical roles in germ cell formation and differentiation in the prawn. Thus, MnTdrd can be used as a novel germ cell marker to trace the origin and migration of germ cells.

生殖细胞特异性基因在有性生物生殖系统的建立中发挥着重要作用，并已被用作研究配子发生和性别分化的有价值的标记。此前，我们分离了vasa转录本作为生殖细胞标记，以追踪东方河虾日本沼虾生殖细胞的起源和迁移。在这里，我们鉴定了一种新的生殖细胞特异性标记MnTdrd RNA，并评估了其在卵子发生和胚胎发生过程中的时间和空间表达。MnTdrd转录本在未受精卵和卵裂期胚胎中高丰度表达，然后在胚胎发生后期显着下降，表明MnTdrd mRNA 是母系遗传的。卵巢组织原位杂交显示，MnTdrd mRNA最初存在于卵黄发生前卵母细胞的细胞质中，并随着卵黄发生期间卵黄的积累而定位于核周区域。胚胎的整体原位杂交表明，MnTdrd阳性信号仅定位于一个卵裂球，直至 16 细胞阶段。在囊胚中，大约有 16 个MnTdrd阳性卵裂球。在胚胎化幼虫阶段，MnTdrd阳性细胞聚集成簇并迁移到生殖器雏形，该生殖器雏形将发育成原始生殖细胞（PGC）。MnTdrd转录本的局部表达模式与之前鉴定的生殖细胞标记vasa的局部表达模式相似，支持生殖细胞规范的预形成模式。因此，我们得出结论，MnTdrd与vasa一起是种质的组成部分，可能在对虾生殖细胞的形成和分化中发挥关键作用。因此，MnTdrd可以作为一种新的生殖细胞标记物来追踪生殖细胞的起源和迁移。