Razani Babak, Park David S, Miyanaga Yuko, Ghatpande Ashwini, Cohen Justin, Wang Xiao Bo, Scherer Philipp E, Evans Todd, Lisanti Michael P
Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Biochemistry. 2002 Jun 25;41(25):7914-24. doi: 10.1021/bi020043n.
Caveolae are approximately 50-100 nm invaginations of the plasma membrane thought to form as a result of a local accumulation of cholesterol, sphingolipids, and a unique family of three proteins known as the caveolins: Cav-1, -2, and -3. Here, we report the identification, sequence, and developmental expression of the three caveolin genes in the amphibian Xenopus laevis. Sequence comparisons show that Xenopus Cav-1, -2, and -3 are approximately 80, 64, and 45% identical, respectively, to their counterparts in humans. Furthermore, Northern blotting experiments demonstrate that the Xenopus caveolins have tissue-specific expression profiles consistent with those previously reported in adult mammals. In the adult frog, Xenopus Cav-1 and Cav-2 are most abundantly expressed in the fat body and the lungs, while Xenopus Cav-3 is primarily expressed in muscle tissue types (heart and skeletal muscle). However, our temporal and spatial analyses of these expression patterns during embryogenesis reveal several novel features, with possible relevance to developmental signaling. Transcripts encoding Xenopus Cav-1 and -2 first appear in the notochord of neurula stage embryos, which represents a key signaling tissue. In contrast, Xenopus Cav-3 shows a highly specific punctate expression pattern in the embryonic epidermis, similar to previous patterns implicated in Notch signaling. These findings are in striking contrast to their steady-state expression patterns in the adult frog. Taken together, our results show that the Xenopus caveolin gene family is present and differentially expressed in both embryonic and adult tissues. This report is the first detailed study of caveolin gene expression in a developing embryo.
小窝是质膜上约50 - 100纳米的内陷结构，被认为是由于胆固醇、鞘脂以及一组独特的三种蛋白质（即小窝蛋白家族：Cav - 1、- 2和- 3）的局部积累而形成的。在此，我们报告了非洲爪蟾中这三种小窝蛋白基因的鉴定、序列及发育表达情况。序列比较表明，非洲爪蟾的Cav - 1、- 2和- 3分别与人的对应蛋白约有80%、64%和45%的同一性。此外，Northern印迹实验表明，非洲爪蟾小窝蛋白具有与成年哺乳动物中先前报道一致的组织特异性表达谱。在成年蛙中，非洲爪蟾Cav - 1和Cav - 2在脂肪体和肺中表达最为丰富，而非洲爪蟾Cav - 3主要在肌肉组织类型（心脏和骨骼肌）中表达。然而，我们对胚胎发育过程中这些表达模式的时空分析揭示了几个新特征，可能与发育信号传导有关。编码非洲爪蟾Cav - 1和- 2的转录本首先出现在神经胚期胚胎的脊索中，脊索是一个关键的信号组织。相比之下，非洲爪蟾Cav - 3在胚胎表皮中呈现高度特异性的点状表达模式，类似于先前与Notch信号传导相关的模式。这些发现与它们在成年蛙中的稳态表达模式形成了鲜明对比。综上所述，我们的结果表明非洲爪蟾小窝蛋白基因家族在胚胎和成年组织中均存在且差异表达。本报告是对发育胚胎中小窝蛋白基因表达的首次详细研究。
