CELL-SURFACE GLYCOPROTEINS AND PLACE-DEPENDENT SUPPRESSION OF CELL PROLIFERATION

越来越多的证据表明，细胞表面相关糖蛋白具有 在调节参与生长的初级过程中的重要作用， 植物和动物的发展。 Edelman（1988）创造了这个术语 “地形生物学”涵盖一系列与地点有关的相互作用 由某些细胞表面相关糖蛋白介导， 与质膜（CAM）相关或分泌到 细胞外基质（SAMs）。 这些分子与 介导细胞-细胞识别/粘附、细胞分化和细胞凋亡 在动物的分裂过程中。 我们在扩展这个概念 包括植物的发育。 虽然肯定会有 在细胞中起作用的调节分子的特定差异 植物和动物的表面，似乎有可能， 在真核生物中， 相似 在这方面，我们已开始探讨 某些糖蛋白，阿拉伯半乳聚糖蛋白（ACP），与 植物细胞表面具有与CAM和/或SAM类似的功能 在动物发展中。 我们正集中精力处理依赖于地点的问题， 控制细胞增殖，因为它在正常和 植物和动物的不正常发育。 在植物中，AGP包括 一个大的含羟脯氨酸的糖蛋白家族，与 质膜和细胞外基质。 我们所获得 有证据表明，AGPs可能参与抑制植物细胞分裂。 当我们的“模式”物种之一的植物，Gymnocolea膨胀， 在一组条件下，特定叶原基中的细胞分裂是 抑制 当在第二组条件下培养时， 在这些原基中是“去抑制的”。 与去抑制 细胞分裂是具有浮力的“特定”AGPs的消失， 密度在1.66和1.64之间。 这些AGP是否在抑制 细胞分裂的位置依赖性抑制 我们将尝试回答 本课题通过使用CsCl密度梯度和HPLC分离AGP， 随着抑制/去抑制细胞分裂而变化的组分， 免疫细胞化学程序，以确定是否特异性AGP部分， 与细胞分裂的位置依赖性抑制有关。

Evidence is accumulating that cell surface-associated glycoproteins have important roles in regulating primary processes involved in the growth and development of both plants and animals. Edelman (1988) has coined the term "Topobiology" to encompass the range of place-dependent interactions mediated by certain cell surface-associated glycoproteins that are associated with the plasma membrane (CAMs) or excreted into the extracellular matrix (SAMs). These molecules have been implicated in mediating cell-cell recognition/adhesion, cell differentiation, and cell division, among other processes, in animals. We are extending the concept of topobiology to include plant development. Although there are certain to be specific differences in the regulatory molecules operating at the cell surfaces of plants and animals, it seems possible that the mechanisms underlying similar developmental processes in eukaryotic organisms will be similar. In this context, we have begun to explore the possibility that certain glycoproteins, arabinogalactan proteins (ACPs), associated with plant cell surfaces have some functions analogous to the CAMs and/or SAMs in animal development. We are focusing our efforts on the place-dependent control of cell proliferation because of its pivotal role in normal and abnormal development of both plants and animals. In plants, AGPs comprise a large family of hydroxyproline-containing glycoproteins associated with both the plasma membranes and the extracellular matices. We have obtained evidence that AGPs may be involved in suppressing cell division in plants. When plants of one of our "model" species, Gymnocolea inflata, are cultured under one set of conditions, cell division in specific leaf primordia is suppressed. When cultured under a second set of conditions, cell division in these primordia is "desuppressed". Correlated with the desuppression of cell division is the disappearance of "specific" AGPs having buoyant densities between 1.66 and 1.64. Do these AGPs have a role in suppressing a place-dependent suppression of cell division? We will attempt to answer this question by use of CsC1 density gradients and HPLC to isolate AGP fractions that change with suppressed/desuppressed cell division and immunocytochemical procedures to determine if specific AGP moieties are associated with the place-dependent suppression of cell division.