Skeath J B
Department of Genetics, 4566 Scott Avenue, Washington University School of Medicine, St. Louis, MO 63110, USA.
Bioessays. 1999 Nov;21(11):922-31. doi: 10.1002/(SICI)1521-1878(199911)21:11<922::AID-BIES4>3.0.CO;2-T.
The specification of specific and often unique fates to individual cells as a function of their position within a developing organism is a fundamental process during the development of multicellular organisms. The development of the Drosophila embryonic central nervous system serves as an excellent model system in which to clarify the developmental mechanisms that link pattern formation to cell-type specification. The Drosophila embryonic central nervous system develops from a set of neural stem cells termed neuroblasts. Neuroblasts arise from the ectoderm in an invariant pattern, and each neuroblast acquires a unique fate based on its position within this pattern. Two groups of genes recently have been demonstrated to govern the individual fate specification of neuroblasts. One group, the segment polarity genes, enables neuroblasts that develop in different anteroposterior positions to acquire different fates. The second group, referred to as the columnar genes, ensures that neuroblasts that develop in different dorsoventral domains assume different fates. When integrated, the activities of the segment polarity and columnar genes create a Cartesian coordinate system that bestows unique fates to individual neuroblasts as a function of their position of formation within the ectoderm. BioEssays 1999;21:922-931.
作为发育中的生物体中细胞位置的函数，赋予单个细胞特定且通常独特的命运，是多细胞生物体发育过程中的一个基本过程。果蝇胚胎中枢神经系统的发育是一个极好的模型系统，可用于阐明将模式形成与细胞类型特化联系起来的发育机制。果蝇胚胎中枢神经系统由一组称为神经母细胞的神经干细胞发育而来。神经母细胞以不变的模式从外胚层产生，每个神经母细胞根据其在该模式中的位置获得独特的命运。最近已证明两组基因控制神经母细胞的个体命运特化。一组是节段极性基因，它使在不同前后位置发育的神经母细胞获得不同的命运。第二组称为柱状基因，确保在不同背腹区域发育的神经母细胞具有不同的命运。当整合时，节段极性基因和柱状基因的活动创建了一个笛卡尔坐标系，根据神经母细胞在外胚层内的形成位置赋予其独特的命运。《生物论文》1999年；21:922 - 931。
