Suwansa-Ard Saowaros, Zhao Min, Thongbuakaew Tipsuda, Chansela Piyachat, Ventura Tomer, Cummins Scott F, Sobhon Prasert
Department of Anatomy, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4558, Australia.
Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4558, Australia.
Gen Comp Endocrinol. 2016 Sep 15;236:70-82. doi: 10.1016/j.ygcen.2016.07.008. Epub 2016 Jul 9.
Crustacean neuropeptides (NPs) play important roles in the regulation of most physiological activities, including growth, molting and reproduction. In this study, we have performed an in silico analysis of female prawn (Macrobrachium rosenbergii) neural transcriptomes to identify NPs not previously identified. We predict that approximately 1309 proteins are destined for the secretory pathway, many of which are likely post-translationally processed to generate active peptides. Within this neural secretome, we identified a gene transcript that encoded a precursor protein with striking similarity to a gonadotropin-releasing hormone (GnRH). We additionally identified another GnRH NP superfamily member, the adipokinetic hormone/corazonin-related peptide (ACP). M. rosenbergii GnRH and ACP were widespread throughout the nervous tissues, implicating them as potential neuromodulators. Furthermore, GnRH was found in non-neural tissues, including the stomach, gut, heart, testis and ovary, in the latter most prominently within secondary oocytes. The GnRH/corazonin receptor-like gene is specific to the ovary, whereas the receptor-like gene expression is more widespread. Administration of GnRH had no effect on ovarian development and maturation, nor any effect on total hemolymph lipid levels, while ACP administration decreased oocyte proliferation (at high dose) and stimulated a significant increase in total hemolymph lipids. In conclusion, our targeted analysis of the M. rosenbergii neural secretome has revealed the decapod GnRH and ACP genes. We propose that ACP in crustaceans plays a role in the lipid metabolism and the inhibition of oocyte proliferation, while the role of the GnRH remains to be clearly defined, possibly through experiments involving gene silencing.
甲壳类动物神经肽（NPs）在大多数生理活动的调节中发挥着重要作用，包括生长、蜕皮和繁殖。在本研究中，我们对雌性罗氏沼虾的神经转录组进行了计算机分析，以鉴定此前未被鉴定的神经肽。我们预测约有1309种蛋白质会进入分泌途径，其中许多可能会经过翻译后加工以产生活性肽。在这个神经分泌组中，我们鉴定出一个基因转录本，它编码一种与促性腺激素释放激素（GnRH）具有显著相似性的前体蛋白。我们还鉴定出了GnRH神经肽超家族的另一个成员，即脂肪动激素/心钠素相关肽（ACP）。罗氏沼虾的GnRH和ACP广泛分布于神经组织中，表明它们可能是潜在的神经调节剂。此外，在包括胃、肠道、心脏、睾丸和卵巢在内的非神经组织中也发现了GnRH，在卵巢中，GnRH在次级卵母细胞中最为显著。GnRH/心钠素受体样基因在卵巢中具有特异性，而受体样基因的表达则更为广泛。注射GnRH对卵巢发育和成熟没有影响，对血淋巴总脂质水平也没有任何影响，而注射ACP则会降低卵母细胞增殖（高剂量时），并刺激血淋巴总脂质显著增加。总之，我们对罗氏沼虾神经分泌组的靶向分析揭示了十足目动物的GnRH和ACP基因。我们提出，甲壳类动物中的ACP在脂质代谢和抑制卵母细胞增殖中发挥作用，而GnRH的作用仍有待明确界定，可能需要通过涉及基因沉默的实验来确定。
