ABSTRACT The molecular mechanisms underlying sex differentiation and gonad development remain elusive in crustaceans. Here, we report the cloning and characterization of a Sry-related high-mobility group family B2 gene (SpSoxB2) from an economic crustacean species, the mud crab Scylla paramamosain. The SpSoxB2 encodes a putative HMG-box protein (317 amino acids) clustered with invertebrate Sox14 homologues in the SoxB2 subgroup, but shared low similarity with SpSox14. SpSoxB2 was expressed in the hepatopancreas, thoracic ganglion, and gonads (relatively higher expression in testis than ovary). In hepatopancreas, SpSoxB2 expression was not significantly affected by sex or gonadal development stages. In testis, it was demonstrated that the SpSoxB2 expression level increased from Stage I to Stage III and then decreased afterwards. During ovarian development, the SpSoxB2 expression level continually increased from Stage I to Stage V. Furthermore, fluorescence in-situ hybridization showed that SpSoxB2 transcripts were present in both somatic and developing germ cells in the gonads. In testis, SpSoxB2 transcripts were strongly localized in spermatocytes and spermatids. In ovary, SpSoxB2 transcripts were detected in follicle cells, oogonia and oocytes, with the strongest signal in follicle cells. Our results demonstrated that the SpSoxB2 gene may play an important role during gonadal development in mud crab.

中文翻译：

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与泥蟹（Scylla paramamosain）性腺发育相关的SoxB2基因的分子克隆、表征和表达谱

摘要 甲壳类动物的性别分化和性腺发育的分子机制仍然难以捉摸。在这里，我们报告了来自经济甲壳类物种泥蟹 Scylla paramamosain 的 Sry 相关高迁移率族 B2 基因 (SpSoxB2) 的克隆和表征。SpSoxB2 编码推定的 HMG-box 蛋白（317 个氨基酸），与 SoxB2 亚群中的无脊椎动物 Sox14 同源物聚集在一起，但与 SpSox14 的相似性较低。SpSoxB2 在肝胰腺、胸神经节和性腺中表达（在睾丸中的表达相对高于卵巢）。在肝胰腺中，SpSoxB2 表达不受性别或性腺发育阶段的显着影响。在睾丸中，已证明 SpSoxB2 表达水平从阶段 I 增加到阶段 III，然后降低。在卵巢发育过程中，SpSoxB2 表达水平从 I 期到 V 期持续增加。此外，荧光原位杂交显示 SpSoxB2 转录物存在于性腺的体细胞和发育中的生殖细胞中。在睾丸中，SpSoxB2 转录物强烈定位于精母细胞和精子细胞中。在卵巢中，在卵泡细胞、卵原细胞和卵母细胞中检测到 SpSoxB2 转录物，在卵泡细胞中信号最强。我们的结果表明 SpSoxB2 基因可能在泥蟹性腺发育过程中发挥重要作用。SpSoxB2 转录本强烈定位于精母细胞和精子细胞中。在卵巢中，在卵泡细胞、卵原细胞和卵母细胞中检测到 SpSoxB2 转录物，在卵泡细胞中信号最强。我们的结果表明 SpSoxB2 基因可能在泥蟹性腺发育过程中发挥重要作用。SpSoxB2 转录本强烈定位于精母细胞和精子细胞中。在卵巢中，在卵泡细胞、卵原细胞和卵母细胞中检测到 SpSoxB2 转录物，在卵泡细胞中信号最强。我们的结果表明 SpSoxB2 基因可能在泥蟹性腺发育过程中发挥重要作用。