Differential gene expression in the liver of the African lungfish, Protopterus annectens, after 6 days of estivation in air
Differential gene expression in the liver of the African lungfish, Protopterus annectens, after 6 days of estivation in air
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DOI：
10.1007/s00360-011-0613-z
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发表时间：
2012-02-01
影响因子：
2
通讯作者：
Ip, Y. K.
中科院分区：
文献类型：
--
作者：
Loong, A. M.;Hiong, K. C.;Ip, Y. K.
本研究旨在利用抑制减法杂交聚合酶链反应，通过测定黏液茧在空气（常氧环境）中羽化6天后肝脏中差异基因的表达，来鉴定羽化特异性基因群。我们的研究结果表明，在正常缺氧条件下饲养6天，导致几种与尿素合成相关的基因mRNA表达上调，包括磷酸氨甲酰合成酶（Cps）、精氨酸琥珀酸合成酶和谷氨酰胺合成酶。这表明，尽管尿素合成是能量密集型的，但它是一种重要的适应性反应。它们还间接支持了这种肺鱼的尿素合成涉及以谷氨酰胺为底物的Cps的命题。此外，在正常缺氧条件下饲养6天后，肝内多个基因簇出现了上调或下调。这些睡眠特异性基因参与预防血块形成、激活补体激活的凝集素途径、保护矿物质（如铁和铜）以及增加血红蛋白β的产生。由于核糖体蛋白和翻译延伸因子相关基因的mRNA表达上调和下调，在休眠的前6天（诱导期），蛋白质降解和蛋白质合成可能同时增加，证实了蛋白质结构重建对准备休眠维持期的重要性。
This study aimed to identify estivation-specific gene clusters through the determination of differential gene expressions in the liver of Protopterus annectens after 6 days of estivation in a mucus cocoon in air (normoxia) using suppression subtractive hybridization polymerase chain reaction. Our results demonstrated that 6 days of estivation in normoxia led to up-regulation of mRNA expressions of several genes related to urea synthesis, including carbamoyl phosphate synthetase (Cps), argininosuccinate synthetase and glutamine synthetase. They indicate that increased urea synthesis, despite being energy-intensive, is an important adaptive response of estivation. They also offer indirect support to the proposition that urea synthesis in this lungfish involved a Cps that uses glutamine as a substrate. In addition, up- or down-regulation of several gene clusters occurred in the liver of P. annectens after 6 days of estivation in normoxia. These estivation-specific genes were involved in the prevention of clot formation, activation of the lectin pathway for complement activation, conservation of minerals (e.g. iron and copper) and increased production of hemoglobin beta. Since there were up- and down-regulation of mRNA expressions of genes related to ribosomal proteins and translational elongation factors, there could be simultaneous increases in protein degradation and protein synthesis during the first 6 days (the induction phase) of estivation, confirming the importance of reconstruction of protein structures in preparation for the maintenance phase of estivation.