Fat facets interacts with Vasa in the Drosophila pole plasm and protects it from degradation
Fat facets interacts with Vasa in the Drosophila pole plasm and protects it from degradation
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DOI：
10.1016/j.cub.2003.10.026
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发表时间：
2003-10-28
期刊：
影响因子：
9.2
通讯作者：
Lasko, P
中科院分区：
文献类型：
--
作者：
Liu, NK;Dansereau, DA;Lasko, P
在果蝇中，前-后模式和生殖细胞特化需要在卵子发生期间建立一个称为极浆的特化细胞质区域[1，2]。大量的RNA和蛋白质积累到极浆中并组装成极粒。这些RNA中的一些的翻译通常被抑制并且仅在极质中活跃[1，2]。Vasa [VAS]蛋白是一种RNA解旋酶，也是极性颗粒的一种组分，在母体中对于后部图案形成和生殖细胞特化至关重要，VAS是极浆中的候选翻译激活剂[3，4]。VAS在极细胞质中是稳定的，因为它最初存在于整个胚胎中，但在细胞胚盘阶段严格限于极细胞[5]。另一个例子是hsp 83 mRNA，它通过稳定-降解机制在极细胞质中积累[6]。在这里，我们使用生物化学方法来鉴定交联提取物中与VAS共纯化的蛋白质。这些蛋白质中最突出的是泛素特异性蛋白酶脂肪小面（FAF），一种极浆组分[7]，但其在后部图案化和生殖系特化中的作用仍不清楚。我们提出的证据表明，FAF与VAS物理相互作用，逆转VAS泛素化，从而稳定极血浆中的VAS。
Anterior-posterior patterning and germ cell specification in Drosophila requires the establishment, during oogenesis, of a specialized cytoplasmic region termed the pole plasm [1, 2]. Numerous RNAs and proteins accumulate to the pole plasm and assemble in polar granules. Translation of some of these RNAs is generally repressed and active only in pole plasm [1, 2]. Vasa [VAS] protein, an RNA helicase and a component of polar granules, is essential maternally for posterior patterning and germ cell specification, and VAS is a candidate translational activator in the pole plasm [3, 4]. VAS is stabilized within the pole plasm in that it is initially present throughout the entire embryo but strictly limited to the pole cells by the cellular blastoderm stage [5]. hsp83 mRNA, which accumulates in the pole plasm through a stabilization-degradation mechanism [6], is another example. Here, we used a biochemical approach to identify proteins that copurify with VAS in crosslinked extracts. Prominent among these proteins was the ubiquitin-specific protease Fat facets (FAF), a pole plasm component [7], but one whose roles in posterior patterning and germ line specification have remained unclear. We present evidence that FAF interacts with VAS physically and reverses VAS ubiquitination, thereby stabilizing VAS in the pole plasm.