Cholinesterases and cell proliferation in “nonstratified” and “stratified” cell aggregates from chicken retina and tectum
Cholinesterases and cell proliferation in “nonstratified” and “stratified” cell aggregates from chicken retina and tectum
复制标题
鸡视网膜和顶盖“非分层”和“分层”细胞聚集体中的胆碱酯酶和细胞增殖
作者：
G. Vollmer;P. Layer
摘要鸡视网膜或顶盖分离的单细胞在旋转介导的细胞培养物中聚集、增殖并建立一定程度的组织学细胞间关系（“分选”），但这些系统从不形成高度分层的聚集体（“非分层”R-和T-聚集体）。相反，视网膜细胞和色素上皮细胞的混合物形成高度“分层”的聚集体（“RPE聚集体”，参见Vollmer等，1984）。目前的比较研究“分层”和“非分层”的聚集体，使我们能够调查的过程中，细胞增殖解耦的组织分层。在这里，我们试图将这两个基本的神经发生过程与胆碱酯酶（AChE，BChE）的表达模式，在形成两种类型的aggregate.During早期聚集体形成，在“分层”和“非分层”聚集体增加丁酰胆碱酯酶活性观察接近有丝分裂活跃的细胞。两种现象在培养2-3天后均显示出最大值。相反，在所有系统中的乙酰胆碱酯酶的表达增加与孵育时间。在非增殖性区域，在RPE聚集体的中心，丛状层的形成的特点是最初由弱BChE，然后强AChE活性。这些区域对应于体内视网膜的内部（IPL）和外部（OPL）丛状层。尽管通过蔗糖梯度离心我们发现AChE的6S-和纤维相关的11 S-分子存在于所有类型的聚集体中，但在培养期间，11 S/6S-型的比率仅在RPE-聚集体中增加，这再次表明这些聚集体中的分化程度较高。这表明了两种酶在两个发育时期的功能。
SummaryDissociated single cells from chicken retina or tectum kept in rotation-mediated cell culture aggregate, proliferate and establish a certain degree of histotypical cellto-cell relationships (“sorting out”), but these systems never form highly laminated aggregates (“nonstratified” R- and T-aggregates). In contrast, a mixture of retinal plus pigment epithelial cells forms highly “stratified” aggregates (“RPE-aggregates”, see Vollmer et al. 1984). The present comparative study of “stratified” and “nonstratified” aggregates enables us to investigate the process of cell proliferation uncoupled from that of tissue stratification. Here we try to relate these two basic neurogenetic processes with patterns of expression of cholinesterases (AChE, BChE) during formation of both types of aggregates.During early aggregate formation, in both “stratified” and “nonstratified” aggregates an increased butyrylcholinesterase activity is observed close to mitotically active cells. Quantitatively both phenomena show their maxima after 2–3 days in culture. In contrast, AChE-expression in all systems increases with incubation time. In nonproliferative areas, in the center of RPE-aggregates, the formation of plexiform layers is characterized initially by weak BChE and then strong AChE-activity. These areas correspond with the inner (IPL) and outer (OPL) plexiform layers of the retina in vivo. Although by sucrose gradient centrifugation we find that the 6S- and the fiber-associated 11S-molecules of AChE are present in all types of aggregates, during the culture period the ratio of 11S/6S-forms increases only in RPE-aggregates, which again indicates the advanced degree of differentiation within these aggregates.It is thus demonstrated that cholinesterases first correlate with neuronal cell proliferation and later with stratification, which indicates functions of both enzymes during both developmental periods.