在果蝇中，与确定身体轴线有关的oskar mRNA是由卵母细胞(oocyte)附近的保姆细胞(nurse cells)产生的，并且必须在oskar mRNA开始翻译蛋白质之前被转运到卵母细胞。
最近，德国海德堡的欧洲分子生物学实验室(EMBL)的科学家将电子显微镜成像(electron microscopy imaging) 和免疫荧光(immunofluorescence)方法相结合，发现了上述oskar mRNA定位过程的分子机制。
在发表于Cell杂志的研究报告中，他们首次发现，当oskar mRNA从保姆细胞的细胞核出来进入到细胞质后，会被立即安装上两种马达蛋白——驱动蛋白(kinesin)和动力蛋白(dynein)，RNA在这两种马达蛋白的协助下，最终被转运到卵母细胞。（生物谷Bioon.com）
生物谷推荐原始出处：
Cell, Volume 139, Issue 5, 983-998, 25 November 2009 doi:10.1016/j.cell.2009.10.012
Assembly of Endogenous oskar mRNA Particles for Motor-Dependent Transport in the Drosophila Oocyte
Alvar Trucco1, Imre Gaspar1 and Anne Ephrussi1, ,
1 Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
oskar mRNA localization at the oocyte posterior pole is essential for correct patterning of the Drosophila embryo. Here we show at the ultrastructural level that endogenous oskar ribonucleoprotein complexes (RNPs) assemble sequentially with initial recruitment of Hrp48 and the exon junction complex (EJC) to oskar transcripts in the nurse cell nuclei, and subsequent recruitment of Staufen and microtubule motors, following transport to the cytoplasm. oskar particles are non-membrane-bound structures that coalesce as they move from the oocyte anterior to the posterior pole. Our analysis uncovers a role for the EJC component Barentsz in recruiting Tropomyosin II (TmII) to oskar particles in the ooplasm and reveals that TmII is required for kinesin binding to the RNPs. Finally, we show that both kinesin and dynein associate with oskar particles and are the primary microtubule motors responsible for transport of the RNPs within the oocyte.
