Primordial germ cells (PGCs) as the precursors of germ cells are responsible for transmitting genetic information to the next generation. Visualization of teleost PGCs in vivo is essential to research the origination and development of germ cells and facilitate further manipulation on PGCs isolation, cryopreservation, and surrogate breeding. In this study, artificially synthesized mRNAs constructed by fusing fluorescent protein coding region to the 3′ untranslated region (3′UTR) of nanos3 or vasa (mCherry-Smnanos3 3′UTR or mCherry-Smvasa 3′UTR mRNA) were injected into turbot (Scophthalmus maximus) fertilized eggs for tracing PGCs. The results demonstrated that the fluorescent PGCs differentiated from somatic cells and aligned on both sides of the trunk at the early segmentation period, then migrated and located at the dorsal part of the gut where the gonad would form. In the same way, we also found that the zebrafish (Danio rerio) vasa 3′UTR could trace turbot PGCs, while the vasa 3′UTR s of marine medaka (Oryzias melastigma) and red seabream (Pagrus major) failed, although they could label the marine medaka PGCs. In addition, through comparative analysis, we discovered that some potential sequence elements in the3 ′UTRs of nanos3 and vasa, such as GCACs, 62-bp U-rich regions and nucleotide 187–218 regions might be involved in PGCs stabilization. The results of this study provided an efficient, rapid, and specific non-transgenic approach for visualizing PGCs of economical marine fish in vivo.

中文翻译：

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使用由nanos3或vasa基因的3'非翻译区介导的荧光蛋白在体内观察Turbot（Scophthalmus maximus）原始生殖细胞。

作为生殖细胞的前体的原始生殖细胞（PGC）负责将遗传信息传递给下一代。体内硬骨鱼PGC的可视化对于研究生殖细胞的起源和发育以及促进对PGC分离，冷冻保存和替代育种的进一步操作至关重要。在这项研究中，将荧光蛋白编码区与nanos3或vasa的3'非翻译区（3'UTR）融合而构建的人工合成的mRNA （mCherry- Smnanos3 3'UTR或mCherry- Smvasa 3'UTR mRNA）被注入大菱t（巨大）用于追踪PGC的受精卵。结果表明，荧光PGCs从体细胞中分化出来，并在分割早期就在躯干的两侧对齐，然后迁移并位于肠道的生殖腺形成部位。同样，我们还发现斑马鱼（Danio rerio）的vasa 3'UTR可以追踪出大菱形PGC，而海洋marine（Oryzias melastigma）和红鲷（Pagrus major）的vasa 3'UTR失败了，尽管它们可以标记海洋medaka PGC。此外，通过比较分析，我们发现nanos3和vasa的3'UTR中有一些潜在的序列元素，例如GCAC，62bp的富U区域和187-218核苷酸区域可能参与了PGC的稳定。这项研究的结果为可视化体内经济海洋鱼类的PGC提供了一种有效，快速且特定的非转基因方法。