CPEB IS A SPECIFICITY FACTOR THAT MEDIATES CYTOPLASMIC POLYADENYLATION DURING XENOPUS OOCYTE MATURATION
CPEB IS A SPECIFICITY FACTOR THAT MEDIATES CYTOPLASMIC POLYADENYLATION DURING XENOPUS OOCYTE MATURATION
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DOI：
10.1016/0092-8674(94)90547-9
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发表时间：
1994-11-18
期刊：
影响因子：
64.5
通讯作者：
RICHTER, JD
中科院分区：
文献类型：
--
作者：
HAKE, LE;RICHTER, JD
在非洲爪蟾卵母细胞成熟过程中，几种母体mRNA的翻译激活受到细胞质poly（A）延伸的刺激，这需要富含尿苷的细胞质聚腺苷酸化元件（CPE）和六核苷酸AAUAAA。在这里，我们已经丰富了CPE结合蛋白（CPEB）的一步RNA亲和层析，获得了CPEB的cDNA，并评估了CPEB在细胞质聚腺苷酸化的作用。62 kDa的CPEB包含两个RNA识别基序，在这个区域内，它是62%相同的ORB，一个卵母细胞特异性RNA结合蛋白从果蝇。CPEB mRNA和蛋白质在卵母细胞中丰富，在原肠期后的胚胎中未检测到。在卵母细胞成熟期间，CPEB在与多聚腺苷酸化的诱导相对应的时间被磷酸化。免疫耗竭CPEB从多聚腺苷酸化精通鸡蛋提取物使他们不能腺苷酸化外源RNA。通过添加CPEB实现了耗尽提取物中聚腺苷酸化的部分恢复，从而证明该蛋白质是细胞质聚腺苷酸化所需的。
The translational activation of several maternal mRNAs during Xenopus oocyte maturation is stimulated by cytoplasmic poly(A) elongation, which requires the uridine-rich cytoplasmic polyadenylation element (CPE) and the hexanucleotide AAUAAA. Here, we have enriched a CPE-binding protein (CPEB) by single-step RNA affinity chromatography, have obtained a CPEB cDNA, and have assessed the role of CPEB in cytoplasmic polyadenylation. The 62 kDa CPEB contains two RNA recognition motifs, and within this region, it is 62% identical to orb, an oocyte-specific RNA-binding protein from Drosophila. CPEB mRNA and protein are abundant in oocytes and are not detected in embryos beyond the gastrula stage. During oocyte maturation, CPEB is phosphorylated at a time that corresponds with the induction of polyadenylation. Immunodepletion of CPEB from polyadenylation-proficient egg extracts renders them incapable of adenylating exogenous RNA. Partial restoration of polyadenylation in depleted extracts is achieved by the addition of CPEB, thus demonstrating that this protein is required for cytoplasmic polyadenylation.