Programmed cell death in the embryonic central nervous system of Drosophila melanogaster
Programmed cell death in the embryonic central nervous system of Drosophila melanogaster
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DOI：
10.1242/dev.02707
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发表时间：
2007-01-01
期刊：
影响因子：
4.6
通讯作者：
Technau, Gerhard M.
中科院分区：
文献类型：
--
作者：
Rogulja-Ortmann, Ana;Lueer, Karin;Technau, Gerhard M.
尽管程序性细胞死亡（PCD）在果蝇中枢神经系统的发育过程中起着至关重要的作用，但其模式和发生率在很大程度上仍未被研究。我们提供了一个详细的分析PCD的发生在胚胎腹侧神经索（VNC）。我们追踪了PCD的时空格局，并比较了野生型和PCD缺陷H99突变胚胎的胸腹神经粒的外观和总细胞数量。此外，我们通过Dil标记几乎所有神经母细胞，研究了H99突变体中多余细胞的克隆起源和命运，特别注意单个鉴定的神经母细胞谱系中的片段特异性差异。我们的数据显示，尽管pcd缺陷突变体在形态学上结构良好，但VNC中存在明显的增生。大多数神经母细胞系包括多余的细胞，其中一组特定的神经母细胞系表现出片段特异性特征。多余的细胞可以被指定为具有延长的野生型或异常轴突突起的神经元，但不能被指定为胶质细胞。谱系数据还为通常在胚胎晚期死亡的神经母细胞和在胚胎后恢复增殖的神经母细胞的身份提供了指示。使用细胞特异性标记，我们能够精确地识别出一些后代细胞，包括GW神经元、U运动神经元和一个RP运动神经元，所有这些细胞都经历了节段特异性细胞死亡。在此分析中获得的数据为进一步研究PCD调控机制及其在胚胎中枢神经系统片段模式中的作用奠定了基础。
Although programmed cell death (PCD) plays a crucial role throughout Drosophila CNS development, its pattern and incidence remain largely uninvestigated. We provide here a detailed analysis of the occurrence of PCD in the embryonic ventral nerve cord ( VNC). We traced the spatio-temporal pattern of PCD and compared the appearance of, and total cell numbers in, thoracic and abdominal neuromeres of wild-type and PCD-deficient H99 mutant embryos. Furthermore, we have examined the clonal origin and fate of superfluous cells in H99 mutants by Dil labeling almost all neuroblasts, with special attention to segment-specific differences within the individually identified neuroblast lineages. Our data reveal that although PCD-deficient mutants appear morphologically well-structured, there is significant hyperplasia in the VNC. The majority of neuroblast lineages comprise superfluous cells, and a specific set of these lineages shows segment-specific characteristics. The superfluous cells can be specified as neurons with extended wild-type-like or abnormal axonal projections, but not as glia. The lineage data also provide indications towards the identities of neuroblasts that normally die in the late embryo and of those that become postembryonic and resume proliferation in the larva. Using cell-specific markers we were able to precisely identify some of the progeny cells, including the GW neuron, the U motoneurons and one of the RP motoneurons, all of which undergo segment-specific cell death. The data obtained in this analysis form the basis for further investigations into the mechanisms involved in the regulation of PCD and its role in segmental patterning in the embryonic CNS.