Many mRNAs specifically localize within the cytoplasm and are present in RNA-protein complexes. It is generally assumed that localization and complex formation of these RNAs are controlled by trans-acting proteins encoded by genes different than the RNAs themselves. Here, we analyze slow as molasses (slam) mRNA that prominently colocalizes with its encoded protein at the basal cortical compartment during cellularization. The functional implications of this striking colocalization have been unknown. Here, we show that slam mRNA translation is spatiotemporally controlled. We found that translation was largely restricted to the onset of cellularization when Slam protein levels at the basal domain sharply increase. slam mRNA was translated locally, at least partially, as not yet translated mRNA transiently accumulated at the basal region. Slam RNA accumulated at the basal domain only if Slam protein was present. Furthermore, a slam RNA with impaired localization but full coding capacity was only weakly translated. We detected a biochemical interaction of slam mRNA and protein as demonstrated by specific co-immunoprecipitation from embryonic lysate. The intimate relationship of slam mRNA and protein may constitute a positive feedback loop that facilitates and controls timely and rapid accumulation of Slam protein at the prospective basal region.

许多mRNA特异地位于细胞质内，并存在于RNA-蛋白质复合物中。通常认为这些RNA的定位和复杂形成是由与RNA本身不同的基因编码的反式作用蛋白控制的。在这里，我们分析了糖蜜（slam）mRNA在细胞化过程中在基底皮层隔室中与编码蛋白显着共定位的糖蜜（slam）mRNA的缓慢变化。这种惊人的共定位的功能含义是未知的。在这里，我们显示大满贯mRNA的翻译是时空控制的。我们发现，当基础域中的Slam蛋白水平急剧增加时，翻译在很大程度上限于细胞化的开始。大满贯由于尚未翻译的mRNA暂时积累在基底区域，因此mRNA至少局部翻译。仅当存在Slam蛋白时，Slam RNA才会积累在基础结构域中。此外，slam RNA具有受损的本地化，但完整的编码能力只是微弱地翻译。我们检测到了slam mRNA和蛋白质的生化相互作用，这是通过从胚胎裂解物中进行特异性免疫共沉淀来证明的。Slam mRNA和蛋白质的密切关系可能会构成一个正反馈回路，从而促进和控制Slam蛋白在预期的基础区域的及时，快速积累。