Huber O, Sumper M
Lehrstuhl Biochemie I, Universität Regensburg, Germany.
EMBO J. 1994 Sep 15;13(18):4212-22. doi: 10.1002/j.1460-2075.1994.tb06741.x.
Proof that plants possess homologs of animal adhesion proteins is lacking. In this paper we describe the generation of monoclonal antibodies that interfere with cell-cell contacts in the 4-cell embryo of the multicellular alga Volvox carteri, resulting in a hole between the cells. The number of following cell divisions is reduced and the cell division pattern is altered drastically. Antibodies given at a later stage of embryogenesis specifically inhibit inversion of the embryo, a morphogenetic movement that turns the embryo inside out. Immunofluorescence microscopy localizes the antigen (Algal-CAM) at cell contact sites of the developing embryo. Algal-CAM is a protein with a three-domain structure: an N-terminal extensin-like domain characteristic for plant cell walls and two repeats with homology to fasciclin I, a cell adhesion molecule involved in the neuronal development of Drosophila. Alternatively spliced variants of Algal-CAM mRNA were detected that are produced under developmental control. Thus, Algal-CAM is the first plant homolog of animal adhesion proteins.
目前尚缺乏植物拥有动物黏附蛋白同源物的证据。在本文中，我们描述了单克隆抗体的产生，这些抗体干扰了多细胞藻类卡特氏团藻4细胞胚胎中的细胞间接触，导致细胞之间出现孔洞。随后的细胞分裂数量减少，细胞分裂模式也发生了巨大改变。在胚胎发生后期给予抗体，会特异性抑制胚胎的内翻，这是一种将胚胎由外向内翻转的形态发生运动。免疫荧光显微镜检查将抗原（藻类钙黏蛋白）定位在发育中胚胎的细胞接触部位。藻类钙黏蛋白是一种具有三结构域的蛋白质：一个N端类伸展蛋白结构域，这是植物细胞壁的特征结构，以及两个与果蝇神经元发育中涉及的细胞黏附分子fasciclin I具有同源性的重复序列。检测到藻类钙黏蛋白mRNA的可变剪接变体，它们是在发育控制下产生的。因此，藻类钙黏蛋白是动物黏附蛋白的首个植物同源物。
