Department of Molecular Biology, College of Life Sciences, Sejong University, 98 Kunja-Dong, Kwangjin-ku, Seoul, South Korea.
Department of Molecular Biology, College of Life Sciences, Sejong University, 98 Kunja-Dong, Kwangjin-ku, Seoul, South Korea.
Biochem Biophys Res Commun. 2014 Jan 31;444(1):98-103. doi: 10.1016/j.bbrc.2014.01.021. Epub 2014 Jan 16.
As a way to spatially control the expression of genes within cells, RNA localization is being recognized as an important process by which proteins are restricted to specific subcellular domains, which occurs in more diverse types of tissue than previously considered. Although many localized RNAs have been identified, information on cis-acting elements of localization is still limited. As transcripts of oskar (osk) are known to localize to the posterior pole of oocytes, we computationally analyzed a conserved sequence among eight Drosophila species and tested its role as a localization element. Dimerization of osk mRNA did not occur when the motif was deleted, but this did not affect assembly of osk mRNA-containing ribonucleoprotein (RNP) complexes. Without the motif, however, large RNP complex particles accumulated in nurse cells, and only a small fraction of these RNP complexes was transported into oocytes and properly localized to the posterior pole. Therefore, this motif may be required for the early transport of osk mRNA into oocytes. Also, as dimerization of osk mRNA does not seem to be a prerequisite for the assembly of RNP complexes, a dimerization-independent mechanism may also serve to localize osk mRNA to the posterior pole.
RNA 定位作为一种在细胞内空间控制基因表达的方式，正被视为一种将蛋白质限制在特定亚细胞区域的重要过程，而这种过程发生在比以前认为的更多样化的组织类型中。尽管已经鉴定出许多定位的 RNA，但关于定位的顺式作用元件的信息仍然有限。由于 Oskar（osk）的转录本已知定位于卵母细胞的后极，我们在计算机上分析了八个果蝇物种之间的保守序列，并测试了其作为定位元件的作用。当缺失该基序时，osk mRNA 的二聚化不会发生，但这并不影响包含 osk mRNA 的核糖核蛋白（RNP）复合物的组装。然而，没有该基序，大型 RNP 复合物颗粒在滋养细胞中积累，只有一小部分这些 RNP 复合物被运入卵母细胞并正确定位于后极。因此，该基序可能是 osk mRNA 早期进入卵母细胞运输所必需的。此外，由于 osk mRNA 的二聚化似乎不是 RNP 复合物组装的先决条件，因此二聚化不依赖的机制也可能有助于将 osk mRNA 定位到后极。
