André E, Lottspeich F, Schleicher M, Noegel A
Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany.
J Biol Chem. 1988 Jan 15;263(2):722-7.
cDNA clones encoding the actin filament severing protein severin from Dictyostelium discoideum were isolated from a cDNA library in lambda gt 11 using monoclonal antibodies. Comparison of the deduced amino acid sequence with the sequence of a severin peptide indicated that the complete coding region of severin is contained in the isolated clones. Severin, a 39.9-kDa protein, is encoded by one gene in D. discoideum. An mRNA of approximately 1.4 kilobases is present throughout the developmental cycle of D. discoideum. The amino acid sequence of severin contains a region highly homologous to a conserved sequence in villin and gelsolin, two proteins of similar function isolated from vertebrates. This homologous region is believed to participate in the actin filament severing activity of these proteins. Comparison of the severin sequence to the entire gelsolin sequence shows remarkable homologies pointing to a common origin from an ancestral gene from which gelsolin has been derived by a duplication.
利用单克隆抗体从λgt 11噬菌体载体构建的盘基网柄菌cDNA文库中分离出了编码肌动蛋白丝切断蛋白——肌割蛋白的cDNA克隆。将推导的氨基酸序列与肌割蛋白肽段的序列进行比较，结果表明分离得到的克隆包含了肌割蛋白完整的编码区。肌割蛋白是一种39.9 kDa的蛋白质，由盘基网柄菌中的一个基因编码。在盘基网柄菌的整个发育周期中都存在一种约1.4千碱基的mRNA。肌割蛋白的氨基酸序列包含一个与绒毛蛋白和凝溶胶蛋白中保守序列高度同源的区域，绒毛蛋白和凝溶胶蛋白是从脊椎动物中分离出的具有相似功能的两种蛋白质。据信这个同源区域参与了这些蛋白质的肌动蛋白丝切断活性。将肌割蛋白序列与整个凝溶胶蛋白序列进行比较，发现了显著的同源性，这表明它们起源于一个共同的祖先基因，凝溶胶蛋白是通过基因复制从该祖先基因衍生而来的。
