Hayakawa Hideki, Andoh Tadashi, Watanabe Toshiki
Division of Molecular Marine Biology, Department of Marine Bioscience, Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan.
Biochem Biophys Res Commun. 2006 May 26;344(1):173-80. doi: 10.1016/j.bbrc.2006.03.116. Epub 2006 Apr 17.
In the egg of the reef coral Galaxea fascicularis, four proteins (named GfEP-1 to -4) are stored in high abundance. In the present study, a cDNA containing a full-length open reading frame for GfEP-1 was cloned, and the translated protein sequence was compared to the N-terminal sequences of GfEP-2, -3, and -4. GfEP-1 and -2 were shown to be generated by processing of a precursor of 1439 amino acids, and GfEP-3 turned out to be a partial fragment of GfEP-2. The precursor protein contained regions which exhibited similarities to vitellogenins (Vgs) in bilaterian animals (oviparous vertebrates and invertebrates including nematodes, arthropods, and molluscs). This study reports the first cloning and characterization of a full-length cDNA encoding a Vg in a non-bilaterian animal, and argues that the emergence of Vg as a precursor of egg yolk proteins predated the divergence of the cnidarian and bilaterian lineages.
在鹿角珊瑚（Galaxea fascicularis）的卵中，四种蛋白质（命名为GfEP - 1至 - 4）大量储存。在本研究中，克隆了一个包含GfEP - 1全长开放阅读框的cDNA，并将翻译后的蛋白质序列与GfEP - 2、 - 3和 - 4的N端序列进行了比较。结果表明，GfEP - 1和 - 2是由一个1439个氨基酸的前体加工产生的，而GfEP - 3原来是GfEP - 2的一个部分片段。该前体蛋白包含与两侧对称动物（卵生脊椎动物和包括线虫、节肢动物和软体动物在内的无脊椎动物）中的卵黄蛋白原（Vgs）相似的区域。本研究报道了非两侧对称动物中首个编码Vg的全长cDNA的克隆和表征，并认为Vg作为卵黄蛋白前体的出现早于刺胞动物和两侧对称动物谱系的分化。
