Dahanukar A, Walker J A, Wharton R P
Howard Hughes Medical Institute, Department of Genetics, Duke University Medical Center, Durham, North Carolina 27710, USA.
Mol Cell. 1999 Aug;4(2):209-18. doi: 10.1016/s1097-2765(00)80368-8.
During Drosophila embryogenesis, a gradient of Nanos protein emanating from the posterior pole organizes abdominal segmentation. This gradient arises from translational regulation of nanos mRNA, which is activated in the specialized cytoplasm at the posterior pole of the embryo and repressed elsewhere. Previously, we have defined cis-acting elements in the mRNA that mediate this translational switch. In this report, we identify a factor named Smaug that binds to these elements and represses translation in the bulk cytoplasm. Smaug interacts gentically and biochemically with Oskar, a key component of the pole plasm for activation of nanos mRNA and specification of the germline precursors. These observations suggest that Smaug operates a translational switch that governs the distribution of Nanos protein.
在果蝇胚胎发育过程中，源自后极的Nanos蛋白梯度组织腹部节段的形成。这种梯度源于nanos mRNA的翻译调控，nanos mRNA在胚胎后极的特化细胞质中被激活，而在其他地方受到抑制。此前，我们已经在mRNA中定义了介导这种翻译转换的顺式作用元件。在本报告中，我们鉴定出一种名为Smaug的因子，它与这些元件结合并抑制大部分细胞质中的翻译。Smaug在遗传和生化水平上与Oskar相互作用，Oskar是极质的关键成分，用于激活nanos mRNA和确定生殖系前体。这些观察结果表明，Smaug操作着一个控制Nanos蛋白分布的翻译开关。
