Brewster R, Bodmer R
Department of Biology, University of Michigan, Ann Arbor, USA.
Dev Genet. 1996;18(1):50-63. doi: 10.1002/(SICI)1520-6408(1996)18:1<50::AID-DVG6>3.0.CO;2-0.
The peripheral nervous system (PNS) of Drosophila provides a very well-characterized model system for studying the genes involved in basic processes of neurogenesis. Because of its simplicity and stereotyped pattern, each cell of the PNS can be individually identified and the phenotypic consequences of mutations can be studied in detail. Thus, some of the genetic mechanisms leading to the formation of type I sensory organs, the external, bristle-type sensory organs (es), and the internal, stretch-receptive chordotonal organs (ch) have been elucidated. Each sensory organ seems to be generated by a stereotyped pattern of cell division of individual ectodermal precursor cells. Recent advances in cell lineage analysis of the PNS have provided a detailed picture of almost all the lineages in the PNS, including those giving rise to the type II sensory neurons, also known as multiple dendritic (md) neurons. This knowledge will be instrumental in the precise characterization of the phenotypes associated with mutations in known and new genes and their interactions which determine cell fate decisions during neurogenesis. Here, we describe and compare three recently developed methods by which cell lineages have been assessed: single cell transplantation, bromodeoxyuridine (BrdU) incorporation studies, and the flp/FRT recombinase system from yeast. In the light of a more complete knowledge of the PNS lineages, we will discuss the effects of known mutations that alter neuronal cell fates.
果蝇的外周神经系统（PNS）为研究参与神经发生基本过程的基因提供了一个特征非常明确的模型系统。由于其简单性和固定模式，PNS的每个细胞都可以单独识别，并且可以详细研究突变的表型后果。因此，一些导致I型感觉器官形成的遗传机制，即外部的刚毛型感觉器官（es）和内部的拉伸感受性弦音器官（ch），已经得到阐明。每个感觉器官似乎都是由单个外胚层前体细胞的固定细胞分裂模式产生的。PNS细胞谱系分析的最新进展提供了PNS中几乎所有谱系的详细图景，包括那些产生II型感觉神经元（也称为多树突状（md）神经元）的谱系。这些知识将有助于精确表征与已知和新基因中的突变相关的表型及其相互作用，这些相互作用决定了神经发生过程中的细胞命运决定。在这里，我们描述并比较了最近开发的三种评估细胞谱系的方法：单细胞移植、溴脱氧尿苷（BrdU）掺入研究以及来自酵母的flp/FRT重组酶系统。鉴于对PNS谱系有了更完整的了解，我们将讨论改变神经元细胞命运的已知突变的影响。
