DIFFERENT FORMS OF SOLUBLE CYTOPLASMIC MESSENGER-RNA BINDING-PROTEINS AND PARTICLES IN XENOPUS-LAEVIS OOCYTES AND EMBRYOS
DIFFERENT FORMS OF SOLUBLE CYTOPLASMIC MESSENGER-RNA BINDING-PROTEINS AND PARTICLES IN XENOPUS-LAEVIS OOCYTES AND EMBRYOS
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DOI：
10.1083/jcb.112.1.1
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发表时间：
1991-01-01
影响因子：
7.8
通讯作者：
FRANKE, WW
中科院分区：
文献类型：
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作者：
MURRAY, MT;KROHNE, G;FRANKE, WW
为了深入了解非洲爪蟾发育过程中母体储存的mRNP形成的机制，我们寻找能够选择性结合mRNA的卵母细胞可溶性胞质蛋白，使用放射性标记的mRNA作为底物。 在溶液中的体外mRNP组装之后是UV交联和RNA酶消化，导致通过核苷酸转移共价标记多肽。 已发现约54、56、60、70和100 kD的五种多肽（p54、p56、p60、p70和p100）选择性结合mRNA并组装成mRNP。 这些多肽对应于先前描述的天然mRNP组分，存在于三种不同的颗粒类别中，分别为约4.5S、约6S;而大约4.5S的类别包含p42、p60和p70，可能每一种都是单独的分子或小复合物的形式，大约6S的颗粒似乎仅由p54和p56组成，它们以接近化学计量的比例出现，提示异二聚体复合物。 除了p54和p56之外，大约15 S的颗粒还含有p60和p100，这是RNA结合p100的单一存在形式。 我们还观察到这些多肽在卵子发生和早期胚胎发育过程中的体外mRNA结合特性的变化，与它们的磷酸化状态和大约15 S颗粒相关蛋白激酶的活性有关，这表明这些蛋白质参与了母体mRNA的发育翻译调控。
To gain insight into the mechanisms involved in the formation of maternally stored mRNPs during Xenopus laevis development, we searched for soluble cytoplasmic proteins of the oocyte that are able to selectively bind mRNAs, using as substrate radiolabeled mRNA. In vitro mRNP assembly in solution was followed by UV-cross-linking and RNase digestion, resulting in covalent tagging of polypeptides by nucleotide transfer. Five polypeptides of approximately 54, 56, 60, 70, and 100 kD (p54, p56, p60, p70, and p100) have been found to selectively bind mRNA and assemble into mRNPs. These polypeptides, which correspond to previously described native mRNP components, occur in three different particle classes of approximately 4.5S, approximately 6S,; and approximately 15S, as also determined by their reactions with antibodies against p54 and p56.Whereas the approximately 4.5S class contains p42, p60, and p70, probably each in the form of individual molecules or small complexes, the approximately 6S particles appear to consist only of p54 and p56, which occur in a nearstoichiometric ratio suggestive of a heterodimer complex. The approximately 15S particles contain, in addition to p54 and p56, p60 and p100 and this is the single occurring form of RNA-binding p100. We have also observed changed in the in vitro mRNA binding properties of these polypeptides during oogenesis and early embryonic development, in relation to their phosphorylation state and to the activity of an approximately 15S particle-associated protein kinase, suggesting that these proteins are involved in the developmental translational regulations of maternal mRNAs.