Styhler S, Nakamura A, Swan A, Suter B, Lasko P
Department of Biology, McGill University, Montréal, Quèbec, Canada H3A 1B1, Canada.
Development. 1998 May;125(9):1569-78. doi: 10.1242/dev.125.9.1569.
The Drosophila gene vasa is required for pole plasm assembly and function, and also for completion of oogenesis. To investigate the role of vasa in oocyte development, we generated a new null mutation of vasa, which deletes the entire coding region. Analysis of vasa-null ovaries revealed that the gene is involved in the growth of germline cysts. In vasa-null ovaries, germaria are atrophied, and contain far fewer developing cysts than do wild-type germaria; a phenotype similar to, but less severe than, that of a null nanos allele. The null mutant also revealed roles for vasa in oocyte differentiation, anterior-posterior egg chamber patterning, and dorsal-ventral follicle patterning, in addition to its better-characterized functions in posterior embryonic patterning and pole cell specification. The anterior-posterior and dorsal-ventral patterning phenotypes resemble those observed in gurken mutants. vasa-null oocytes fail to efficiently accumulate many localized RNAs, such as Bicaudal-D, orb, oskar, and nanos, but still accumulate gurken RNA. However, GRK accumulation in the oocyte is severely reduced in the absence of vasa function, suggesting a function for VASA in activating gurken translation in wild-type ovaries.
果蝇基因vasa是极质组装和功能所必需的，也是卵子发生完成所必需的。为了研究vasa在卵母细胞发育中的作用，我们产生了一种新的vasa无效突变，该突变删除了整个编码区。对vasa缺失卵巢的分析表明，该基因参与生殖系囊肿的生长。在vasa缺失的卵巢中，生殖腺萎缩，与野生型生殖腺相比，发育中的囊肿要少得多；这种表型与无效nanos等位基因的表型相似，但程度较轻。无效突变体还揭示了vasa在卵母细胞分化、前后卵室模式形成以及背腹卵泡模式形成中的作用，此外它在胚胎后模式形成和极细胞特化中具有更好描述的功能。前后和背腹模式形成表型类似于在gurken突变体中观察到的表型。vasa缺失的卵母细胞不能有效地积累许多定位RNA，如双尾-D、orb、osk和nanos，但仍能积累gurken RNA。然而，在没有vasa功能的情况下，卵母细胞中的GRK积累严重减少，这表明VASA在野生型卵巢中激活gurken翻译具有一定作用。
