The transforming growth factor-β (TGF-β) signaling pathway is conserved across animals, and knowledge of its roles during the molt cycle in crustaceans is presently very limited. This study investigates the roles of the TGF-β receptor in molting-related muscle growth in Eriocheir sinensis. Using the RT-PCR and RACE techniques, we obtained a 1722 bp cDNA sequence encoding a transforming growth factor-β type I receptor in Eriocheir sinensis, designated EsTGFBRI, which contains a 124 bp 5′-untranslated region, a 20 bp partial 3′-untranslated region and a 1578 bp open reading frame encoding 525 amino acids. The deduced EsTGFBRI contains an N-terminal 24 amino acid signal peptide, an activin type I and II receptor domain, a transmembrane helix region, a glycine-serine-rich motif, and a conserved serine/threonine kinase catalytic domain including an activation loop. The qRT-PCR results showed that EsTGFBRI gene was highly expressed in the intermolt testis and ovary in mature crabs. In juvenile crabs, the mRNA levels of EsTGFBRI in claw and abdominal muscles in the later premolt D_3–4 stage were significantly higher than those in the intermolt C and postmolt A–B stages. There was no significant change in EsTGFBRI mRNA levels in walking leg muscles during the molt cycle. The results suggest that EsTGFBRI is probably play roles in molting-related muscle growth in E. sinensis. This study provides a necessary basis for elucidating the functions of TGF-β-like signaling mediated by TGFBRI in molting-related muscle growth in crustaceans.

中文翻译：

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中华绒螯蟹中转化生长因子-βI型受体转录物的鉴定及其在肌肉组织中的蜕皮相关表达

转化生长因子-β（TGF-β）信号转导通路在整个动物中都是保守的，关于其在甲壳类动物蜕皮周期中的作用的知识目前非常有限。本研究探讨了TGF-β受体在中华绒螯蟹蜕皮相关肌肉生长中的作用。利用RT-PCR和RACE技术，我们在中华绒螯蟹中获得了一个1722 bp的cDNA序列，该cDNA编码转化生长因子-βI型受体。命名为EsTGFBRI，其包含124bp的5'非翻译区，20bp的部分3'非翻译区和1578bp的开放阅读框，其编码525个氨基酸。推导的EsTGFBRI包含一个N端24个氨基酸信号肽，一个激活素I和II型受体域，一个跨膜螺旋区，一个富含甘氨酸-丝氨酸的基序和一个保守的丝氨酸/苏氨酸激酶催化域，包括一个激活环。qRT-PCR结果表明，EsTGFBRI基因在成熟蟹的蜕膜间睾丸和卵巢中高表达。在幼蟹中，前蜕皮D _3–4中爪和腹肌中EsTGFBRI的mRNA水平蜕皮期明显高于中间蜕皮期和蜕皮后AB期。在蜕皮周期中，步行的腿部肌肉中EsTGFBRI mRNA水平没有明显变化。结果表明，EsTGFBRI可能在中华绒毛蜕皮相关的肌肉生长中起作用。该研究为阐明TGFBRI介导的TGF-β样信号转导与甲壳动物蜕皮相关的肌肉生长的功能提供了必要的基础。