Schuldt A J, Adams J H, Davidson C M, Micklem D R, Haseloff J, St Johnston D, Brand A H
Wellcome/CRC Institute and Department of Genetics, Cambridge CB2 1QR, UK.
Genes Dev. 1998 Jun 15;12(12):1847-57. doi: 10.1101/gad.12.12.1847.
Neuroblasts undergo asymmetric stem cell divisions to generate a series of ganglion mother cells (GMCs). During these divisions, the cell fate determinant Prospero is asymmetrically partitioned to the GMC by Miranda protein, which tethers it to the basal cortex of the dividing neuroblast. Interestingly, prospero mRNA is similarly segregated by the dsRNA binding protein, Staufen. Here we show that Staufen interacts in vivo with a segment of the prospero 3' UTR. Staufen protein and prospero RNA colocalize to the apical side of the neuroblast at interphase, but move to the basal side during prophase. Both the apical and basal localization of Staufen are abolished by the removal of a conserved domain from the carboxyl terminus of the protein, which interacts in a yeast two-hybrid screen with Miranda protein. Furthermore, Miranda colocalizes with Staufen protein and prospero mRNA during neuroblast divisions, and neither Staufen nor prospero RNA are localized in miranda mutants. Thus Miranda, which localizes Prospero protein, also localizes prospero RNA through its interaction with Staufen protein.
神经母细胞进行不对称干细胞分裂以产生一系列神经节母细胞（GMCs）。在这些分裂过程中，细胞命运决定因子Prospero通过Miranda蛋白不对称地分配到GMC中，Miranda蛋白将其束缚在分裂的神经母细胞的基皮质上。有趣的是，prospero mRNA同样由双链RNA结合蛋白Staufen进行分离。在这里我们表明，Staufen在体内与prospero 3'UTR的一段相互作用。在间期，Staufen蛋白和prospero RNA共定位于神经母细胞的顶端，但在前期移至基部。通过从该蛋白的羧基末端去除一个保守结构域，消除了Staufen在顶端和基部的定位，该保守结构域在酵母双杂交筛选中与Miranda蛋白相互作用。此外，在神经母细胞分裂期间，Miranda与Staufen蛋白和prospero mRNA共定位，并且在miranda突变体中Staufen和prospero RNA均未定位。因此，定位Prospero蛋白的Miranda也通过其与Staufen蛋白的相互作用来定位prospero RNA。
