Matsuzaki F, Ohshiro T, Ikeshima-Kataoka H, Izumi H
Department of Molecular Genetics, National Institute of Neuroscience, NCNP, Kodaira, Tokyo 187, Japan.
Development. 1998 Oct;125(20):4089-98. doi: 10.1242/dev.125.20.4089.
When neuroblasts divide, prospero protein and mRNA segregate asymmetrically into the daughter neuroblast and sibling ganglion mother cell. miranda is known to localize prospero protein to the basal cell cortex of neuroblasts while the staufen RNA-binding protein mediates prospero mRNA localization. Here we show that miranda is required for asymmetric staufen localization in neuroblasts. Analyses using miranda mutants reveal that prospero and staufen interact with miranda under the same cell-cycle-dependent control. miranda thus acts to partition both prospero protein and mRNA. Furthermore, miranda localizes prospero and staufen to the basolateral cortex in dividing epithelial cells, which express the three proteins prior to neurogenesis. Our observations suggest that the epithelial cell and neuroblast (both of epithelial origin) share the same molecular machinery for creating cellular asymmetry.
当神经母细胞分裂时，prospero蛋白和mRNA不对称地分离到子神经母细胞和同胞神经节母细胞中。已知miranda将prospero蛋白定位到神经母细胞的基底细胞皮层，而staufen RNA结合蛋白介导prospero mRNA的定位。在这里我们表明，miranda是神经母细胞中staufen不对称定位所必需的。使用miranda突变体的分析表明，prospero和staufen在相同的细胞周期依赖性控制下与miranda相互作用。因此，miranda起到了分隔prospero蛋白和mRNA的作用。此外，miranda在分裂的上皮细胞中将prospero和staufen定位到基底外侧皮层，这些上皮细胞在神经发生之前表达这三种蛋白。我们的观察结果表明，上皮细胞和神经母细胞（均起源于上皮）共享用于产生细胞不对称性的相同分子机制。
