Rao Y, Bodmer R, Jan L Y, Jan Y N
Howard Hughes Medical Institute, University of California, San Francisco 94143-0724.
Development. 1992 Sep;116(1):31-40. doi: 10.1242/dev.116.1.31.
big brain (bib) is one of the six known zygotic neurogenic genes involved in the decision of an ectodermal cell to take on the neurogenic or the epidermogenic cell fate. Previous studies suggest that bib functions in a pathway separate from the one involving Notch and other known neurogenic genes. For a better understanding of the bib function, it is essential first to characterize the mutant phenotype in detail. Our mutant analyses show that loss of bib function approximately doubles the number of neuronal precursors and their progeny cells in the embryonic peripheral nervous system. Mosaic studies reveal a hypertrophy of sensory bristles in bib mutant patches in adult flies. Our observations are compatible with a function of bib in specifying neuronal precursors of both the embryonic and adult sensory nervous system. This is in contrast to the function of Notch, which continues to be required at multiple stages of neural development subsequent to this initial determination event.
大头脑基因（bib）是已知的六个合子神经发生基因之一，参与外胚层细胞决定成为神经发生细胞或表皮发生细胞命运的过程。先前的研究表明，bib在一条与涉及Notch和其他已知神经发生基因的途径不同的途径中发挥作用。为了更好地理解bib的功能，首先详细表征突变体表型至关重要。我们的突变体分析表明，bib功能丧失使胚胎外周神经系统中神经元前体及其子代细胞的数量增加了约一倍。镶嵌研究揭示了成年果蝇bib突变体斑块中感觉刚毛的肥大。我们的观察结果与bib在指定胚胎和成年感觉神经系统的神经元前体中的功能一致。这与Notch的功能形成对比，Notch在这一初始决定事件后的神经发育多个阶段仍持续发挥作用。
