Development of Segment Specificity in Identified Lineages of the CNS

已识别的中枢神经系统谱系的片段特异性的发展

• 批准号: 9601385
• 负责人: Melody V. S. Siegler
• 金额: $ 23.95万
• 依托单位: Emory University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9601385&HistoricalAwards=false
• 关键词: Development; Segment; Specificity; Identified; Lineages

IBN 9601385 PI: Melody V.S. Siegler The nervous system has segmental populations of neurons that are diversified to meet the requirements of sensory and motor processing along the length of an animal's body. The work to be performed assesses the contributions of two cellular processes to segmental diversification and specialization during the course of embryonic development: cell proliferation and cell death. In a model system, Schistocerca americana, each segment of the central nervous system develops from an array of neuroblasts, each of which can be identified as an individual. Each neuroblast produces a "family" of clonally related neurons. For example, one neuroblast in each segment, called the median neuroblast (MNB), generates a family of neurons containing neurons of two different types, motor neurons, which innervate muscles, and interneurons, which interconnect sensory and motor neurons. In the thoracic segments the MNB families contain about 100 neurons, 20 of which are motor neurons. In the abdominal segments the MNB families contain about 50 neurons, only 3 of which are motor neurons. The idea will be tested that the MNBs, and other neuroblasts in anterior segments, divide at about twice the rate of the comparable neuroblasts in the posterior segments, initially generating neuronal pools of larger or smaller sizes. In addition, the role of cell death in setting the final population size of neuroblast families will be investigated . Cell death appears to remove many neurons in abdominal regions, but few neurons in thoracic regions, providing a second mechanism for generating larger thoracic and smaller abdominal segments. Related studies will focus on the hypothesis that there are domains of cell death and of cell proliferation that correspond roughly, but not precisely, to thoracic and abdominal regions. Their imprecise overlap leads to three rather than two potential outcomes, thus: a large neuronal population results from high proliferation rates and low cell death, an int ermediate neuronal population results from high proliferation rates and high cell death, and a small neuronal population results from low proliferation rates and high cell death. Knowledge of how these fundamental cellular processes shape segmental identity is crucial to an understanding of development of the mature central nervous system.

IBN 9601385 PI：Melody V.S.西格勒 神经系统具有神经元的节段群体，这些神经元是多样化的，以满足沿着动物身体沿着的感觉和运动处理的要求。要进行的工作评估的贡献，两个细胞过程中的部分多样化和专业化的胚胎发育过程中：细胞增殖和细胞死亡。在一个模型系统中，美洲血吸虫，中枢神经系统的每一部分都是从一系列成神经细胞中发育而来的，每一个成神经细胞都可以被识别为一个个体。每个神经母细胞产生一个克隆相关神经元的“家族”。例如，每个节段中的一个神经母细胞，称为正中神经母细胞（MNB），产生一个神经元家族，包含两种不同类型的神经元，运动神经元和中间神经元，运动神经元支配肌肉，中间神经元将感觉神经元和运动神经元互连。在胸段中，MNB家族包含约100个神经元，其中20个是运动神经元。在腹节中，MNB家族包含约50个神经元，其中只有3个是运动神经元。 这个想法将被测试，MNB，和其他神经母细胞在前段，分裂率约为两倍的可比神经母细胞在后段，最初产生较大或较小的大小的神经元池。此外，将研究细胞死亡在设定成神经细胞家族的最终群体大小中的作用。细胞死亡似乎去除了腹部区域的许多神经元，但胸部区域的神经元很少，这为产生更大的胸部和更小的腹部节段提供了第二种机制。 相关的研究将集中在这样一个假设上，即细胞死亡和细胞增殖的区域大致对应于胸部和腹部区域，但并不精确。它们的不精确重叠导致三个而不是两个潜在的结果，因此：大的神经元群体的结果从高增殖率和低细胞死亡，中间的神经元群体的结果从高增殖率和高细胞死亡，和一个小的神经元群体的结果从低增殖率和高细胞死亡。 了解这些基本的细胞过程是如何形成节段特性的，对于理解成熟的中枢神经系统的发育至关重要。