Rørth P
Department of Embryology, Carnegie Institution of Washington, 115 West University Parkway, Baltimore, MD 21210, USA.
Mech Dev. 1998 Nov;78(1-2):113-8. doi: 10.1016/s0925-4773(98)00157-9.
The modular Gal4 system has proven to be an extremely useful tool for conditional gene expression in Drosophila. One limitation has been the inability of the system to work in the female germline. A modified Gal4 system that works throughout oogenesis is presented here. To achieve germline expression, it was critical to change the basal promoter and 3'-UTR in the Gal4-responsive expression vector (generating UASp). Basal promoters and heterologous 3'-UTRs are often considered neutral, but as shown here, can endow qualitative tissue-specificity to a chimeric transcript. The modified Gal4 system was used to investigate the role of the Drosophila FGF homologue branchless, ligand for the FGF receptor breathless, in border cell migration. FGF signaling guides tracheal cell migration in the embryo. However, misexpression of branchless in the ovary had no effect on border cell migration. Thus border cells and tracheal cells appear to be guided differently.
模块化Gal4系统已被证明是在果蝇中进行条件性基因表达的极为有用的工具。该系统的一个局限性在于无法在雌性生殖系中发挥作用。本文介绍了一种在整个卵子发生过程中起作用的改良Gal4系统。为了实现生殖系表达，改变Gal4应答表达载体中的基础启动子和3'非翻译区（产生UASp）至关重要。基础启动子和异源3'非翻译区通常被认为是中性的，但如下所示，它们可以赋予嵌合转录本定性的组织特异性。改良的Gal4系统被用于研究果蝇FGF同源物无分支（FGF受体呼吸急促的配体）在边界细胞迁移中的作用。FGF信号传导引导胚胎中的气管细胞迁移。然而，无分支在卵巢中的错误表达对边界细胞迁移没有影响。因此，边界细胞和气管细胞似乎受到不同的引导。
