Havin L, Git A, Elisha Z, Oberman F, Yaniv K, Schwartz S P, Standart N, Yisraeli J K
Department of Anatomy and Cell Biology, Hebrew University Medical School, Jerusalem 91120, Israel.
Genes Dev. 1998 Jun 1;12(11):1593-8. doi: 10.1101/gad.12.11.1593.
Vg1 mRNA translocation to the vegetal cortex of Xenopus oocytes requires intact microtubules, and a 3' UTR cis-acting element (termed VLE), which also mediates sequence-specific binding of several proteins. One protein, the 69-kD Vg1 RBP, associates Vg1 RNA to microtubules in vitro. Here we show that Vg1 RBP-binding sites correlate with vegetal localization. Purification and cloning of Vg1 RBP revealed five RNA-binding motifs: four KH and one RRM domains. Surprisingly, Vg1 RBP is highly homologous to the zipcode binding protein implicated in the microfilament-mediated localization of beta actin mRNA in fibroblasts. These data support Vg1 RBP's direct role in vegetal localization and suggest the existence of a general, evolutionarily conserved mechanism for mRNA targeting.
Vg1信使核糖核酸（mRNA）转运至非洲爪蟾卵母细胞的植物性皮质需要完整的微管，以及一个3'非翻译区顺式作用元件（称为VLE），该元件也介导几种蛋白质的序列特异性结合。一种蛋白质，即69-kD Vg1核糖核蛋白结合蛋白（Vg1 RBP），在体外使Vg1核糖核酸（RNA）与微管结合。我们在此表明，Vg1 RBP结合位点与植物性定位相关。Vg1 RBP的纯化与克隆揭示了五个RNA结合基序：四个KH结构域和一个RNA识别基序（RRM）结构域。令人惊讶的是，Vg1 RBP与参与成纤维细胞中β肌动蛋白mRNA微丝介导定位的邮政编码结合蛋白高度同源。这些数据支持Vg1 RBP在植物性定位中的直接作用，并表明存在一种通用的、进化上保守的信使核糖核酸（mRNA）靶向机制。
