Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America.
Sci Rep. 2017 Oct 18;7(1):13457. doi: 10.1038/s41598-017-13613-8.
Diatoms are known for their intricate, silicified cell walls (frustules). Silica polymerization occurs in a compartment called the silica deposition vesicle (SDV) and it was proposed that the cytoskeleton influences silica patterning through the SDV membrane (silicalemma) via interactions with transmembrane proteins. In this work we identify a family of proteins associated with the silicalemma, named SAPs for Silicalemma Associated Proteins. The T. pseudonana SAPs (TpSAPs) are characterized by their motif organization; each contains a transmembrane domain, serine rich region and a conserved cytoplasmic domain. Fluorescent tagging demonstrated that two of the TpSAPs were localized to the silicalemma and that the intralumenal region of TpSAP3 remained embedded in the silica while the cytoplasmic region was cleaved. Knockdown lines of TpSAP1 and 3 displayed malformed valves; which confirmed their roles in frustule morphogenesis. This study provides the first demonstration of altering silica structure through manipulation of a single gene.
硅藻以其复杂的硅化细胞壁（壳）而闻名。硅的聚合发生在一个称为硅沉积小泡（SDV）的隔室中，有人提出细胞骨架通过与跨膜蛋白的相互作用，通过 SDV 膜（硅质膜）影响硅的图案化。在这项工作中，我们鉴定了一组与硅质膜相关的蛋白质，命名为 SAPs（Silicalemma Associated Proteins）。拟菱形藻 SAPs（TpSAPs）的特征是其基序组织；每个都包含一个跨膜结构域、富含丝氨酸的区域和一个保守的细胞质结构域。荧光标记表明，两种 TpSAP 定位于硅质膜上，TpSAP3 的内腔区域仍然嵌入在二氧化硅中，而细胞质区域被切割。TpSAP1 和 3 的敲低系显示出畸形的瓣；这证实了它们在壳形态发生中的作用。本研究首次通过操纵单个基因来改变二氧化硅结构提供了证据。
