Triacylglycerides (TAG) are a pivotal nutrient for crustacean reproduction, rapidly accumulating in gonads and hepatopancreas during the ovary development. Glycerol‐3‐phosphate acyltransferase (GPAT) is the enzyme catalyzing the first step in TAG synthesis. In the present study, two EsGPATs subtypes (EsGPAT1 and EsGPAT2) were identified and characterized. The transcript of EsGPAT1 was highly expressed in thoracic ganglia, hepatopancreas and ovary, while EsGPAT2 was mainly detected in nervous tissues and intestine. During the ovary development, in hepatopancreas, the expression levels of EsGPAT1 increased from Stage I to its maximum at Stage IV and then declined sharply. The transcription levels of EsGPAT2 were highest at Stage I and then gradually declined to reach its minimum at Stage IV. In ovaries, the EsGPAT1 expression levels increased from Stage I to reach its maximum at Stage IV and then declined. The transcription levels of EsGPAT2 reached the peak at Stage I and then declined to the minimum at Stage III. In situ hybridization revealed they were both located in the F cells and R cells of hepatopancreas and all types of cells at Stage I, the follicle cells and the exogenous vitellogenic oocytes at Stage III and nearly mature oocytes at Stage IV of the ovary. In addition, the knockdown of EsGPAT1 downregulated the expression levels of downstream genes in TAG synthesis pathway, but it was not observed in RNAi treatment group of EsGPAT2. These results indicate that the two EsGPATs identified have different roles in TAG metabolism during the ovarian development of E. sinensis.

中文翻译：

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中华绒螯蟹卵巢发育过程中不同调控三酰甘油合成的两种亚型的3-磷酸甘油酰基转移酶的鉴定和功能表达。

甘油三酸酯（TAG）是甲壳类动物繁殖的关键营养素，在卵巢发育过程中会迅速在性腺和肝胰腺中蓄积。甘油3-磷酸酰基转移酶（GPAT）是催化TAG合成第一步的酶。在本研究中，鉴定并鉴定了两种EsGPATs亚型（EsGPAT1和EsGPAT2）。EsGPAT1的转录物在胸神经节，肝胰脏和卵巢中高表达，而EsGPAT2主要在神经组织和肠中检测到。在卵巢发育过程中，肝胰腺中EsGPAT1的表达水平从第一阶段上升到第四阶段的最大值，然后急剧下降。EsGPAT2的转录水平在第一阶段最高，然后逐渐下降，在第四阶段达到最低。在卵巢中，EsGPAT1表达水平从I期开始升高，到IV期达到最高，然后下降。EsGPAT2的转录水平在阶段I达到峰值，然后在阶段III降至最低。原位杂交表明，它们都位于肝胰腺的F细胞和R细胞中，并且位于I期的所有类型的细胞，III期的卵泡细胞和外源性卵黄母细胞以及IV期的接近成熟的卵母细胞。此外，EsGPAT1的敲低下调TAG合成途径中下游基因的表达水平，但在EsGPAT2的RNAi治疗组中未观察到。这些结果表明，鉴定的两个EsGPATs在中华绒螯蟹卵巢发育过程中TAG代谢中的作用不同。