Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, Bielefeld, 33615, Germany.
Plant J. 2020 Sep;103(6):2301-2317. doi: 10.1111/tpj.14901. Epub 2020 Jul 27.
Hydroxyproline-rich glycoproteins (HRGPs) constitute a major group of proteins of the extracellular matrix (ECM). The multicellular green alga Volvox carteri is a suitable model organism in which to study the evolutionary transition to multicellularity, including the basic principles and characteristics of an ECM. In Volvox, the ECM is dominated by a single HRGP family: the pherophorins. Our inventory amounts to 117 pherophorin-related genes in V. carteri. We focused on a pherophorin with an unexpected characteristic: pherophorin-S is a soluble, non-cross-linked ECM protein. Using transformants expressing a YFP-tagged pherophorin-S we observed the synthesis and secretion of pherophorin-S by somatic cells in vivo, and we then traced the protein during its conspicuous migration to the ECM around prehatching juveniles and its localized concentration there. Our results provide insights into how an ECM zone surrounding the progeny is remotely affected by distantly located parental somatic cells. In view of the properties and migration of pherophorin-S, we conclude that pherophorin-S is likely to act as an ECM plasticizer to allow for dynamic ECM remodeling.
羟脯氨酸丰富的糖蛋白（HRGPs）构成细胞外基质（ECM）的主要蛋白质组。多细胞绿藻衣藻是研究向多细胞性进化的合适模式生物，包括 ECM 的基本原理和特征。在衣藻中，ECM 主要由单一的 HRGP 家族：pherophorins 组成。我们在 V. carteri 中鉴定出 117 个 pherophorin 相关基因。我们专注于一种具有意外特征的 pherophorin：pherophorin-S 是一种可溶性、非交联的 ECM 蛋白。使用表达 YFP 标记的 pherophorin-S 的转化体，我们观察到体细胞在体内合成和分泌 pherophorin-S，然后追踪该蛋白在明显迁移到预孵化幼体周围的 ECM 中的过程及其在那里的局部集中。我们的结果提供了关于如何通过远距离的亲代体细胞远程影响子代周围 ECM 区的见解。鉴于 pherophorin-S 的性质和迁移，我们得出结论，pherophorin-S 可能充当 ECM 增塑剂，以允许动态的 ECM 重塑。
