Spana E P, Doe C Q
Howard Hughes Medical Institute, Department of Cell and Structural Biology, University of Illinois, Urbana 61801, USA.
Neuron. 1996 Jul;17(1):21-6. doi: 10.1016/s0896-6273(00)80277-9.
Asymmetric cell divisions play a key role in establishing neuronal diversity in the mammalian and Drosophila CNS, but the mechanisms involved are mostly unknown. The Drosophila MP2 precursor divides asymmetrically to generate the dMP2/vMP2 interneurons. Delta-Notch signaling is required to specify vMP2 fate, whereas the localized determinant Numb is segregated into dMP2 and is required to specify dMP2 fate. Notch; numb double mutants have two dMP2 neurons; hence, Numb is not required for dMP2 fate, but antagonizes the Delta-Notch "vMP2" signal. In vivo Delta expression and in vitro culture experiments show that vMP2 fate is specified by an "inductive" signal from outside the MP2 lineage. Thus, intrinsic and extrinsic cues converge to specify binary cell fates in the MP2 cell lineage.
不对称细胞分裂在哺乳动物和果蝇的中枢神经系统中建立神经元多样性方面起着关键作用，但其中涉及的机制大多未知。果蝇MP2前体细胞进行不对称分裂以产生dMP2/vMP2中间神经元。Delta-Notch信号传导是确定vMP2命运所必需的，而定位决定因子Numb被分离到dMP2中，是确定dMP2命运所必需的。Notch;numb双突变体有两个dMP2神经元；因此，Numb对于dMP2命运不是必需的，但它拮抗Delta-Notch“vMP2”信号。体内Delta表达和体外培养实验表明，vMP2命运是由MP2谱系外的“诱导”信号确定的。因此，内在和外在线索共同作用以确定MP2细胞谱系中的二元细胞命运。
