CELL PROLIFERATION IN DEVELOPING HIPPOCAMPAL REGION

细胞数量的调节，更具体地说，是对神经元数量的调节 开发CNS在很大程度上是一个未被探索的问题。对此有什么答案吗 问题必须考虑两个重要的发展问题：1) 神经元产生的调节和2)自然的 正在发生细胞死亡。本项目涉及其中的第一个 问题。我们将确定：1)增殖性细胞的相对数量如何 细胞在结构发育过程中的变化，2)细胞变化的频率 增殖性细胞分裂，以及3)增殖性细胞 每经过一次细胞，群体就会永久地处于有丝分裂后状态 周而复始。我们将在四个不同的增殖区研究这个问题 在发育中的小鼠海马区：1)脑室 海马区和下丘脑区，2)脑室区 皮质周围(小叶前、下丘旁和内嗅区，3) 皮质周围的脑室下区，以及4)肺门内 齿状回的增殖区。我们将测量的长度 细胞周期(T_C)和DNA合成期(T_S) 对于扩散的人口以及将 产生神经元。在几个年龄段，子代细胞的比例 这使得增殖区成为永久的有丝分裂后意愿 决心测试这样一个假设，即在发展过程中 比例逐渐增加，以至于不断增长的人口 在细胞增殖前几代变得自我耗尽 这种结构将不复存在。增殖区的产出将是 通过确定离开每个 一小时内的四个增殖种群(即，一小时 来自逆转录病毒的标记细胞的分布模式 四种不同增殖物中的三种对后代的感染 人口将被确定。我们将发展三个概率-- 驱动的细胞遗传学和组织遗传学模型、细胞动力学模型和输出 (或细胞增殖)模型和细胞分散模型。模型 将被用于确定各种实验的结果是否 在内部和彼此之间保持一致，使特定的可测试 预测。主要使用的方法有：1)溴脱氧尿苷 免疫组织化学和氚胸苷放射自显影 在一系列双标记实验中，以及2)逆转录病毒 克隆相关群体的转染法。

The regulation of cell number and, more specifically, neuron number in the developing CNS is a largely unexplored question. Any answer to this question must consider two important developmental issues: 1) the regulation of neuronal production and 2) the phenomenon of naturally occurring cell death. This project is concerned with the first of these issues. We will determine: 1) how the relative number of proliferative cells changes during the development of a structure, 2) how frequently the proliferative cells divide, and 3) what proportion of the proliferative population becomes permanently post-mitotic at each pass through the cell cycle. We will examine this issue in four different proliferative zones in the developing hippocampal region of the mouse: 1) the ventricular zone of the hippocampus and subiculum, 2) the ventricular zone of the periallocortex (presubiculum, parasubiculum and entorhinal area, 3) the subventricular zone of the periallocortex, and 4) the intrahilar proliferative zone of the dentate gyrus. We will measure the length of the cell cycle (Tc) and the DNA-synthetic phase (Ts) for all of the proliferative population and also for that subpopulation which will produce neurons. For several ages, the proportion of the daughter cells that leave the proliferative zones to become permanently post-mitotic will be determined to test the hypothesis that during developing that proportion increases gradually such that the proliferative population becomes self-exhausting several generations before cell proliferation for that structure ceases. The output of the proliferative zones will be measured by determining the distribution of cells that leave each of the four proliferative populations within a one-hour period (i.e., a "one-hour cohort"). The pattern of distribution of labeled cells from retroviral infections for progeny from three of the four different proliferative populations will be determined. We will develop three probabilistically- driven cytogenetic and histogenic models, a cytokinetic model, and output (or cell proliferation) model, and a cell dispersion model. The model will be used to determine if the results of the various experiments are consistent internally and with each other and to make specific testable predictions. The major methods to be used are: 1) bromodeoxyuridine immunohistochemistry and tritiated thymidine autoradiography both alone and in a series of double labeling experiments, and 2) retroviral transfection of clonally related populations.