Song Xiaorui, Xin Xiaoyu, Dong Miren, Wang Weilin, Wang Lingling, Song Linsheng
Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian 116023, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China.
Liaoning Key Laboratory of Marine Animal Immunology, Dalian Ocean University, Dalian 116023, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China; Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian 116023, China.
Dev Comp Immunol. 2018 May;82:55-65. doi: 10.1016/j.dci.2018.01.001. Epub 2018 Jan 6.
Hemocytes, the cellular component of invertebrate hemolymph, are essential for invertebrate immunity, but the hematopoiesis and regulation mechanism are still largely unknown. In the present study, a conserved hematopoietic transcription factor Cg-GATA2/3 was identified in Pacific oyster Crassotrea gigas, which was evolutionarily close to the vertebrate GATA1/2/3. Cg-GATA2/3 was mainly distributed in the immune organs, such as gill, hemocytes, and mantle. After Cg-GATA2/3 was interferenced by dsRNA, the mRNA expressions of hemocytes specific gene (EcSOD) and hematopoietic transcription factor (C-Myb) were all significant down-regulated, and the hemocyte renewal rates also decreased both in hemolymph and gill. During the larval developmental stages, the mRNA transcripts of Cg-GATA2/3 increased immediately after fertilization and kept a high level during blastula and early trochophore larvae stage (4-10 hpf, hours post fertilization), then decreased sharply in early D-veliger larvae stage (15 hpf). Whole-mount immunofluorescence assay further revealed that the abundant immunoreactivity of Cg-GATA2/3 was distributed in the whole body of blastula and gastrula embryos, while specialized gradually to a ring structure around the dorsal region in trochophore larvae. In the D-veliger and umbo larvae, scattered positive signals appeared in the specific sinus structure on the dorsal side and velum region. These results demonstrated that Cg-GATA2/3 was a hematopoietic lineage-specific transcription factor to regulate the hemocyte production, and it could also be used as hematopoietic specific marker to trace potential developmental events of hematopoiesis during ontogenesis of oyster.
血细胞是无脊椎动物血淋巴的细胞成分，对无脊椎动物免疫至关重要，但其造血及调控机制仍 largely 未知。在本研究中，在太平洋牡蛎 Crassotrea gigas 中鉴定出一个保守的造血转录因子 Cg-GATA2/3，其在进化上与脊椎动物的 GATA1/2/3 相近。Cg-GATA2/3 主要分布在免疫器官，如鳃、血细胞和外套膜。在用 dsRNA 干扰 Cg-GATA2/3 后，血细胞特异性基因（EcSOD）和造血转录因子（C-Myb）的 mRNA 表达均显著下调，血淋巴和鳃中的血细胞更新率也降低。在幼虫发育阶段，Cg-GATA2/3 的 mRNA 转录本在受精后立即增加，并在囊胚和早期担轮幼虫阶段（受精后 4 - 10 小时）保持高水平，然后在早期 D 形幼虫阶段（15 小时）急剧下降。全组织免疫荧光分析进一步显示 Cg-GATA2/3 的丰富免疫反应性分布在囊胚和原肠胚胚胎的全身，而在担轮幼虫中逐渐特化为围绕背侧区域的环形结构。在 D 形幼虫和壳顶幼虫中，在背侧特定的窦结构和膜区域出现散在的阳性信号。这些结果表明 Cg-GATA2/3 是一种调节血细胞生成的造血谱系特异性转录因子，并且它还可作为造血特异性标记物来追踪牡蛎个体发育过程中造血的潜在发育事件。
