Co-expression and functional interaction of silicatein with galectin -: Matrix-guided formation of siliceous spicules in the marine demosponge Suberites domuncula
Co-expression and functional interaction of silicatein with galectin -: Matrix-guided formation of siliceous spicules in the marine demosponge Suberites domuncula
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DOI：
10.1074/jbc.m512677200
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发表时间：
2006-04-28
影响因子：
4.8
通讯作者：
Müller, WEG
中科院分区：
文献类型：
--
作者：
Schröder, HC;Boreiko, A;Müller, WEG
海绵纲（多孔动物门）的海绵由硅质骨架稳定。它是由硅针（骨针），这提供了这些后生动物的形态发生支架。在针状体的中心有一个轴向的细丝，主要由硅酸盐蛋白组成，硅酸盐蛋白是一种催化生物硅合成的酶。通过差异显示的成绩单，我们确定了其他蛋白质参与二氧化硅的形成。两个基因被分离出的海洋demosponge Suberites domuncula;一个代码的半乳糖凝集素和其他的纤维胶原蛋白。半乳糖凝集素形成与硅酸盐蛋白分子结合的聚集体。如果与半乳糖凝集素相关，则silicatein介导的二氧化硅形成的程度强烈增加。采用一种新的温和的提取方法，避免了氟化氢处理，提取了S. domuncula。这些细丝除了含有硅酸盐蛋白外，还含有半乳糖凝集素和其他一些蛋白质。免疫金电子显微镜研究强调了这些额外的蛋白质，特别是半乳糖凝集素，在毛刺的作用。半乳糖凝集素，除了silicatein，大概形式的轴向管以及表面上的骨针一个有组织的网状矩阵。在视锥外的空间中，这些复合体大多数同心地围绕针状体排列。两者合计，这些额外的蛋白质，与silicatein一起工作，也可能是相关的潜在的（纳米）生物技术应用silicatein在表面涂层的形成。最后，我们提出了一个方案，概述了矩阵（半乳糖凝集素/silicatein）引导的附着生长的针状体通过向心和离心合成和沉积的生物二氧化硅。
Sponges ( phylum Porifera) of the class of Demospongiae are stabilized by a siliceous skeleton. It is composed of silica needles (spicules), which provide the morphogenetic scaffold of these metazoans. In the center of the spicules there is an axial filament that consists predominantly of silicatein, an enzyme that catalyzes the synthesis of biosilica. By differential display of transcripts we identified additional proteins involved in silica formation. Two genes were isolated from the marine demosponge Suberites domuncula; one codes for a galectin and the other for a fibrillar collagen. The galectin forms aggregates to which silicatein molecules bind. The extent of the silicatein-mediated silica formation strongly increased if associated with the galectin. By applying a new and mild extraction procedure that avoids hydrogen fluoride treatment, native axial filaments were extracted from spicules of S. domuncula. These filaments contained, in addition to silicatein, the galectin and a few other proteins. Immunogold electron microscopic studies underscored the role of these additional proteins, in particular that of galectin, in spiculogenesis. Galectin, in addition to silicatein, presumably forms in the axial canal as well as on the surface of the spicules an organized net-like matrix. In the extraspicular space most of these complexes are arranged concentrically around the spicules. Taken together, these additional proteins, working together with silicatein, may also be relevant for potential ( nano)biotechnological applications of silicatein in the formation of surface coatings. Finally, we propose a scheme that outlines the matrix (galectin/silicatein)-guided appositional growth of spicules through centripetal and centrifugal synthesis and deposition of biosilica.