The mechanism of differentiation pattern formation in the cellular slime molds as analysed by monoclonal antibodies

1. 两种类型的细胞（前柄细胞和前孢子细胞）在细胞黏菌细胞聚集形成的组织中分化。我们试图获得每种细胞类型特异性的单克隆抗体，并产生了四种孢子前特异性抗体。与抗体反应的抗原定位于孢子前细胞特异性形成的孢子前液泡中，并在孢子形成时从细胞中释放出来，形成孢子外壳。利用针对某分子种孢子外壳蛋白产生的多克隆抗体，筛选cDNA文库，获得孢子前特异性cDNA克隆，并对该克隆进行基因分离。在获得该基因后，我们将与孢子前细胞中特异性表达的其他基因一起研究其结构和表达调控。作为茎和茎前特异性蛋白，我们纯化了一个WGA结合蛋白（31Kd）和一个与细胞类型非特异性单克隆抗体反应的蛋白（35Kd），但未能制备出单克隆和多克隆抗体。另一方面，利用预茎特异性cDNA克隆获得了大量的特异性蛋白，我们正在针对这些蛋白制备特异性抗体。发现部分多克隆抗孢子抗体和孢子前特异性单克隆抗体与不同种类的盘齿骨菌和多孢子菌抗原发生交叉反应。由于后者的细胞分化尚未得到很好的阐明，我们正在研究利用这些抗体形成模式的过程。一个前柄和前孢子细胞不能分离产生两个假定区域的突变体被分离出来，我们正试图在蛋白质水平上检查突变体的异常。

1. Two types of cells (prestalk and prespore cells) differentiate in a tissue formed by aggregation of cellular slime mold cells. We tried to obtain monoclonal antibodies specific for each cell type and produced four prespore specific antibodies. Antigens reactive with the antibodies are localized in prespore vacuoles specifically formed in prespore cells and released from the cells upon sporulation to constitute spore coat. By using polyclonal antibodies produced against a molecular species of spore coat proteins, a cDNA library was screened to obtain a prespore specific cDNA clone and a gene for this clone is being isolated. After the gene is obtained, we will examine its structure and regulation of expression together with those of other genes specifically expressed in prespore cells.2. As stalk and prestalk specific proteins, we purified a WGA binding protein (31Kd) and a protein (35Kd) reactive with a cell type-nonspecific monoclonal antibody, but failed to produce monoclonal and polyclonal antibodies for either of them. On the other hand, prestalk specific cDNA clones were used to obtain a large amount of specific proteins, against which we are in the process of producing specific antibodies.3. Some of polyclonal antispore antibodies and prespore specific monoclonal antibodies were found to cross-react with antigens of different species of not only Dictyostelium but also Polysphondylium. As cell differentiation in the latter species has not been well elucidated, we are investigating the process of pattern formation by the use of these antibodies.4. A mutant in which prestalk and prespore cells fail to sort out to produce the two presumptive regions was isolated and we are trying to examine the abnormality of the mutant at protein levels.