Identification of mRNAs with polar distributions in complex cells and their functional characterization

许多细胞具有高度极化的形态，具有特殊的功能。在某些细胞类型中，来自局部mRNAs的蛋白质的局部合成有助于细胞行为的极化。我们建议对不同细胞类型中具有极性分布的mRNAs进行遗传筛选，这将基于我们开发的体内筛选方法来识别果蝇气管系统分支细胞中具有极化分布的mRNAs。一项试点筛查已经确定了细胞形态发生所需的基因，这些基因是其他筛查方法所没有发现的。初步结果表明，存在细胞类型特异的mRNA识别和处理系统，并表明该筛选为大规模鉴定可应用于任何细胞类型的局部化RNA提供了一种无偏见的方法。因此，我们在这里提出的本地化mRNAs的全面筛选预计会有两个长期结果。它将产生更多用于阐明细胞形态发生机制的基因，这些基因的序列将构成具有组织特异性极性分布的mRNAs数据库，并为定位信号的生物信息学预测提供基础。我们通过筛选气管细胞、卵母细胞和毛囊细胞上皮而获得的数据库将得到合作实验室的投入，这些实验室将使用我们产生的种群来筛选其他类型的细胞。

Many cells have highly polarized morphologies that serve specialized functions. In some cell types the local synthesis of proteins from localized mRNAs contributes to polarized cell behaviour. We pro-pose here to conduct a genetic screen for mRNAs with polar distributions in different cell types which will be based on an in vivo screening method we have developed to identify mRNAs with polarized distributions in the branched cells of the Drosophila tracheal system. A pilot screen has identified genes required for cell morphogenesis that have not been found by other screening methods. The preliminary results suggest the existence of cell type specific mRNA recognition and processing sys-tems, and show that the screen provides an unbiased approach to large-scale identification of local-ized RNAs that can be applied to any cell type. The full-scale screen for localized mRNAs we propose here is therefore expected to have two long-term results. It will yield further genes for the elucidation of cell morphogenetic mechanisms and the sequences of the genes will constitute a database of mRNAs with tissue-specific polar distributions, and provide a basis for the bioinformatic prediction of localisation signals. Our database obtained from screening tracheal cells,oocytes and the follicle cell epithelium will be enriched by input from collaborating laboratories who will use the stocks we generate to screen other cell types.