在果蠅中,，與確定身體軸線有關(guān)的oskar mRNA是由卵母細(xì)胞(oocyte)附近的保姆細(xì)胞(nurse cells)產(chǎn)生的,，并且必須在oskar mRNA開始翻譯蛋白質(zhì)之前被轉(zhuǎn)運(yùn)到卵母細(xì)胞。
最近,，德國海德堡的歐洲分子生物學(xué)實(shí)驗(yàn)室(EMBL)的科學(xué)家將電子顯微鏡成像(electron microscopy imaging) 和免疫熒光(immunofluorescence)方法相結(jié)合,，發(fā)現(xiàn)了上述oskar mRNA定位過程的分子機(jī)制。
在發(fā)表于Cell雜志的研究報(bào)告中,，他們首次發(fā)現(xiàn),，當(dāng)oskar mRNA從保姆細(xì)胞的細(xì)胞核出來進(jìn)入到細(xì)胞質(zhì)后，會被立即安裝上兩種馬達(dá)蛋白——驅(qū)動蛋白(kinesin)和動力蛋白(dynein),，RNA在這兩種馬達(dá)蛋白的協(xié)助下,，最終被轉(zhuǎn)運(yùn)到卵母細(xì)胞。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
