Undetectable apolipoprotein A-I gene expression suggests an unusual mechanism of dietary lipid mobilisation in the intestine of Cyprinus carpio
Undetectable apolipoprotein A-I gene expression suggests an unusual mechanism of dietary lipid mobilisation in the intestine of Cyprinus carpio
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DOI：
10.1242/jeb.01512
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发表时间：
2005-04-01
影响因子：
2.8
通讯作者：
Amthauer, R
中科院分区：
文献类型：
--
作者：
Concha, MI;López, R;Amthauer, R
高密度脂蛋白(高密度脂蛋白)已被证明在鲤鱼饲料中的脂肪动员中起着重要作用。尽管如此，以往的研究未能证明高密度脂蛋白的主要蛋白质成分载脂蛋白A-I(apoA-I)在鲤鱼的近端肠道中合成。因此，本研究的目的是评估载脂蛋白A-I在整个肠道中的表达。奇怪的是，Northern印迹和RT-PCR方法都没有检测到apoA-I基因在肠粘膜中的转录，这与几乎所有肠段都检测到丰富的胞浆免疫反应apoA-I形成了鲜明的对比，这表明该蛋白的来源不同。此外，在鲤鱼肠道刷状缘膜(BBM)中检测到特异但低亲和力的apoA-I结合部位，以及与BBM的强烈相互作用(高度依赖于温度)，表明膜脂在apoA-I与肠粘膜的结合中做出了重要贡献。鲤鱼apoA-I与多层磷脂小泡结合的能力加强了这一观点。
High density lipoprotein (HDL) has been shown to play an important role in the dietary lipid mobilisation in the carp. In spite of this, previous studies have failed to demonstrate the synthesis of the major protein component of HDL, apolipoprotein A-I (apoA-I), in the proximal intestine of the carp. Therefore, the aim of the present study was to evaluate the expression of apoA-I throughout the entire intestine. Curiously, no transcription of the apoA-I gene could be detected either by northern blot or RT-PCR assays in the intestinal mucosa, in clear contrast with the abundant cytosolic immunoreactive apoA-I detected in almost all intestinal segments, which suggests a different origin for this protein. In addition, the detection of specific, but low affinity, binding sites for apoA-I in the carp intestinal brush-border membranes (BBM), and the strong interaction with BBM, which is highly dependent on temperature, points to an important contribution of membrane lipids in apoA-I binding to the intestinal mucosa. This idea was reinforced by the ability of carp apoA-I to associate with multilamellar phospholipid vesicles.