RIBONUCLEOPROTEINS, MRNA AND CYTOSKELETAL STRUCTURES

信使RNA(MRNAs)，基因表达的中间产物 它们是真核细胞中发现的直接蛋白质合成的物质 与特定的细胞质蛋白质子集相关。这个 MRNA-蛋白质复合体，称为mRNP颗粒(MRNPs)，是 不同的结构赋予不同的蛋白质组成不同的权利， 的结构、功能和亚细胞区划 核蛋白前体(HnRNP)颗粒。过多的 最近的观察表明，mrnp蛋白发挥着重要的作用。 在信使核糖核酸的运输、翻译、稳定性和定位中的作用。 MRNP蛋白可以光化学交联到 在完整细胞和交联物中的mRNA可以 容易被隔离的。我们已经研究了这些络合物在正常和 真核生物中感染病毒的细胞。在所有这些中，最 富含蛋白质是一种72,000道尔顿的蛋白质，它与 信使核糖核酸的聚(A)尾。聚(A)结合蛋白是一种 高度保守、免疫原性差的蛋白质一直是 非常有兴趣的焦点，因为它似乎在 信使核糖核酸代谢。我们用交联剂免疫小鼠 纯化的mRNP复合体产生抗mRNP抗体 蛋白质。获得针对Poly(A)结合蛋白的抗体 来自酵母，我们已经开始描述这种蛋白质的特性 已经分离出了编码它的基因。抗体和基因 是第一个从任何生物体中探测这种蛋白质的探测器，他们 为其分子和基因特征的研究开辟了道路。 我们将研究它的结构、功能、性质和 MRNP蛋白及其与mRNP的复合体的定位 特别强调Poly(A)结合蛋白。其他内容 将产生针对mRNP蛋白的抗体。这些cDNA 这些蛋白质的编码将通过免疫学方法分离出来 表达载体文库的筛选。完整的氨基酸 蛋白质的序列将由核苷酸决定 对cDNA及其mRNAs和基因进行测序 特色化的。蛋白质与RNA的相互作用将是 进行了详细的研究。蛋白质的亚细胞定位将 通过免疫细胞化学技术进行检查。这些功能 的蛋白质将在体内通过基因破坏和 酵母诱变及抗体导入活体的研究 动物细胞，并在体外使用无细胞系统提取蛋白质 合成和信使核糖核酸转录、剪接和聚腺苷酸化。 从这些研究中形成了关于ho mRNA的更好的图景， 在动物细胞中维持和发挥功能的可能性很大。

Messenger RNAs (mRNAs), the intermediates of gene expression which direct protein synthesis, are found in eukaryotic cells associated with a specific subset of cytoplasmic proteins. The mRNA-protein complexes, termed mRNP particles (mRNPs), are distinct structural entitles different in protein composition, structure, function and subcellular compartmentalization from nuclear pre-mRNA-protein (hnRNP) particles. A plethora of recent observations indicate that mRNP proteins play a cardinal role in mRNA transport, translation, stability and localization. The mRNP proteins can be photochemically crosslinked to the mRNA in intact cells and the crosslinked complexes can be readily isolated. We have studied these complexes in normal and virus-infected cells across eukaryotes. In all of these, the most abundant protein is a 72,000 dalton protein which is crosslinked to the poly(A) tail of the mRNA. The poly(A) binding protein is a highly conserved, poorly immunogenic protein that has been the focus of much interest because it appears to play a key role in mRNA metabolism. We have immunized mice with crosslinked purified mRNP complexes to produce antibodies to the mRNP proteins. Antibodies were obtained to the poly(A) binding protein from yeast, and we have begun to characterize the protein and have isolated the gene encoding it. The antibodies and the gene are the first probes for this protein from any organism and they open the way of its molecular and genetic characterization. We shall investigate the structure, function, properties and localization of the mRNP proteins and the mRNP complexes with particular emphasis on the poly(A) binding protein. Additional antibodies to mRNP proteins will be produced. The cDNAs encoding these proteins will be isolated by immunological screening of expression vector libraries. The complete amino acid sequence of the proteins will be determined by nucleotide sequencing of the cDNAs, and their mRNAs and genes will be characterized. The interaction of the proteins with RNA will be studied in detail. The subcellular localization of the proteins will be examined by immunocytochemical techniques. The functions of the proteins will be investigated in vivo by gene disruption and mutagenesis in yeast and by introduction of antibodies into living animal cells, and in vitro using cell free systems for protein synthesis and mRNA transcription, splicing and polyadenylation. From these studies a better picture of ho mRNA is formed, maintained and functions in animal cells is likely to emerge.