EARLY EVENTS IN INSECT NEUROGENESIS .2. THE ROLE OF CELL-INTERACTIONS AND CELL LINEAGE IN THE DETERMINATION OF NEURONAL PRECURSOR CELLS
EARLY EVENTS IN INSECT NEUROGENESIS .2. THE ROLE OF CELL-INTERACTIONS AND CELL LINEAGE IN THE DETERMINATION OF NEURONAL PRECURSOR CELLS
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DOI：
10.1016/0012-1606(85)90446-4
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发表时间：
1985-01-01
影响因子：
2.7
通讯作者：
GOODMAN, CS
中科院分区：
文献类型：
--
作者：
DOE, CQ;GOODMAN, CS
昆虫的中枢神经系统（CNS）由脑和一系列节段性神经节组成，每个半神经节包含约1000个可单独识别的神经元。神经元的多样性和特异性是如何产生的？半神经节的神经元在胚胎发生过程中主要从个体识别的神经元前体细胞（称为成神经细胞（NB））的定型模式中产生。因此，从外胚层到单个神经元的转变涉及两个主要步骤：首先，未分化的外胚层细胞片产生每个半体节30个NB的定型模式;其次，这些NB中的每一个都为发育中的中枢神经系统贡献了一个特定的神经元后代家族。我们已经使用激光微束烧蚀蝗虫胚胎中的单个细胞，以研究神经元决定的初始事件。特别是，一层明显等同的外胚层细胞是如何产生高度定型的独特NB模式的？我们的研究结果表明，以下机制NB的测定。(1)细胞之间的相互作用. apprx.半体节的150个等效外胚层细胞允许30个细胞扩大成NB。(2)当这些年轻的神经母细胞增大时，它们会抑制相邻的外胚层细胞成为神经母细胞;然后相邻的细胞要么分化成非神经元支持细胞，要么死亡。(3)每个NB由于其在神经上皮内的扩大位置而被分配唯一的身份。(4)然后NB通过不变的细胞谱系产生其特征性的神经元家族。昆虫中枢神经系统的发育依赖于细胞相互作用和位置线索以产生NB的模式，然后依赖于细胞谱系以限制NB后代的命运。
The insect central nervous system (CNS) is composed of a brain and a chain of segmental ganglia; each hemiganglion contains about 1000 individually identifiable neurons. How is the enormous neuronal diversity and specificity generated? Neurons of a hemiganglion largely arise during embryogenesis from a stereotyped pattern of individually identified neuronal precursor cells, called neuroblasts (NBs). The transition from ectoderm to individual neurons thus involves two major steps: first, an undifferentiated ectodermal cell sheet produces the stereotyped pattern of 30 NBs per hemisegment; second, each of these NBs contributes a specific family of neuronal progeny to the developing CNS. We have used a laser microbeam to ablate individual cells in the grasshopper embryo in order to study the initial events of neuronal determination. In particular, how does a layer of apparently equivalent ectodermal cells produce a highly stereotyped pattern of unique NBs? Our results suggest the following mechanism for NB determination. (1) Cell interactions between the .apprx. 150 equivalent ectodermal cells of a hemisegment allow 30 cells to enlarge into NBs. (2) As these young NBs enlarge they inhibit adjacent ectodermal cells from becoming NBs; the adjacent cells then either differentiate into nonneuronal support cells or die. (3) Each NB is assigned a unique identity due to its position of enlargement within the neuroepithelium. (4) The NB then generates its characteristic family of neurons by an invariant cell lineage. Development of the insect CNS depends on cell interactions and positional cues to create a pattern of NBs, and then on cell lineage to restrict the fate of the NB progeny.