Tomancak P, Guichet A, Zavorszky P, Ephrussi A
Developmental Biology Programme, European Molecular Biology Laboratory, Heidelberg, Germany.
Development. 1998 May;125(9):1723-32. doi: 10.1242/dev.125.9.1723.
Vasa, a DEAD box mRNA helicase similar to eIF4A, is involved in pole plasm assembly in the Drosophila oocyte and appears to regulate translation of oskar and nanos mRNAs. However, several vasa alleles exhibit a wide range of early oogenesis phenotypes. Here we report a detailed analysis of Vasa function during early oogenesis using novel as well as previously identified hypomorphic vasa alleles. We find that vasa is required for the establishment of both anterior-posterior and dorsal-ventral polarity of the oocyte. The polarity defects of vasa mutants appear to be caused by a reduction in the amount of Gurken protein at stages of oogenesis critical for the establishment of polarity. Vasa is required for translation of gurken mRNA during early oogenesis and for achieving wild-type levels of gurken mRNA expression later in oogenesis. A variety of early oogenesis phenotypes observed in vasa ovaries, which cannot be attributed to the defect in gurken expression, suggest that vasa also affects expression of other mRNAs.
Vasa是一种与真核起始因子4A（eIF4A）类似的DEAD盒mRNA解旋酶，参与果蝇卵母细胞极质的组装，并且似乎调控oskar和nanos mRNA的翻译。然而，几个vasa等位基因表现出广泛的早期卵子发生表型。在此，我们报告了一项利用新的以及先前鉴定的vasa功能减弱等位基因，对早期卵子发生过程中Vasa功能进行的详细分析。我们发现，vasa对于卵母细胞前后轴和背腹轴极性的建立都是必需的。vasa突变体的极性缺陷似乎是由于在卵子发生过程中对极性建立至关重要的阶段，Gurken蛋白量的减少所致。Vasa在早期卵子发生过程中对于gurken mRNA的翻译是必需的，并且在卵子发生后期对于达到gurken mRNA表达的野生型水平也是必需的。在vasa卵巢中观察到的多种早期卵子发生表型，不能归因于gurken表达的缺陷，这表明vasa也影响其他mRNA的表达。
