Hall C, Mahadevan L, Whatley S, Biswas G, Lim L
Biochem J. 1984 May 1;219(3):751-61. doi: 10.1042/bj2190751.
Poly(A)+ RNA (polyadenylated RNA) isolated from membrane-bound and free polyribosomes was translated in reticulocyte lysates, and the products were analysed by two-dimensional gel electrophoresis. Several translation products were specific to membrane-bound polyribosomal mRNA, including polypeptides of 47kDa, 35kDa and 21 kDa, whereas others (e.g. of 37 kDa, 17 kDa and 14 kDa) were specific to free polyribosomal mRNA. Although many products were common to both mRNA species, cross-contamination could be ruled out on the basis of the presence of these and other specific products. The common products included a 68 kDa microtubule-associated protein, tubulin, actin, the brain form of creatine kinase, neuron-specific enolase and protein 14-3-3 and calmodulin, all of which were identified on the basis of two-dimensional gel and peptide analyses. The 35 kDa protein product of membrane-specific mRNA was co-translationally processed in vitro by microsomal membranes, resulting in its cleavage to 33 kDa (and partial glycosylation). The 33 kDa processed protein (but not the 35 kDa precursor) was integrated into both dog pancreas and rat brain microsomal membranes. The occurrence of the enzymes and calmodulin as products of membrane-bound polyribosomal mRNA is discussed in the light of their presence on rat brain synaptic plasma membranes [Lim, Hall, Leung, Mahadevan & Whatley (1983) J. Neurochem. 41, 1177-1182] and their existence in a specific component of axonal flow. It is suggested that some of these translation products of the rough endoplasmic reticulum may represent proteins destined for the plasma membrane. However, the identity and location of the 35 kDa membrane-specific product (or its processed form) still remain unestablished.
从膜结合型和游离型多核糖体中分离出的聚腺苷酸RNA（polyadenylated RNA）在网织红细胞裂解物中进行翻译，并通过二维凝胶电泳对产物进行分析。有几种翻译产物是膜结合型多核糖体mRNA特有的，包括47kDa、35kDa和21kDa的多肽，而其他一些产物（如37kDa、17kDa和14kDa的）则是游离型多核糖体mRNA特有的。尽管许多产物在两种mRNA类型中都有，但基于这些以及其他特异性产物的存在，可以排除交叉污染的可能性。常见产物包括一种68kDa的微管相关蛋白、微管蛋白、肌动蛋白、脑型肌酸激酶、神经元特异性烯醇化酶、蛋白14 - 3 - 3和钙调蛋白，所有这些都是基于二维凝胶和肽分析鉴定出来的。膜特异性mRNA的35kDa蛋白产物在体外被微粒体膜进行共翻译加工，导致其裂解为33kDa（并部分糖基化）。33kDa的加工后蛋白（而非35kDa的前体）整合到犬胰腺和大鼠脑微粒体膜中。根据它们在大鼠脑突触质膜上的存在情况[Lim, Hall, Leung, Mahadevan & Whatley (1983) J. Neurochem. 41, 1177 - 1182]以及它们在轴浆流特定成分中的存在，讨论了这些酶和钙调蛋白作为膜结合型多核糖体mRNA产物的情况。有人提出，粗面内质网的一些这些翻译产物可能代表 destined for the plasma membrane的蛋白质。然而，35kDa膜特异性产物（或其加工形式）的身份和位置仍未确定。 （最后一句中“destined for the plasma membrane”这里表述有误，推测原文想表达“运往质膜”，但按照原文翻译就是“注定质膜”，请确认原文信息）
