大鼠切牙α-磷酸磷蛋白初级基因产物的特性分析

Characterization of the primary gene product of rat incisor alpha-phosphophoryn.

作者信息

Maier G D, Evans J S, Veis A

出版信息

Biochemistry. 1985 Nov 5;24(23):6370-4. doi: 10.1021/bi00344a008.

Abstract

The nature of the primary gene product for the alpha-phosphophoryn component of rat incisor dentin has been examined by cell-free translation of the total RNA and poly(A+) mRNA from rat maxillary incisors, including pulp cells and odontoblasts. The RNA was extracted by the guanidinium thiocyanate method and translated in a rabbit reticulocyte system. The translated proteins were analyzed by gradient gel electrophoresis, and alpha-phosphophoryn was identified by isolation on an anti-rat alpha-phosphophoryn antibody coupled Sepharose column and dot-blot procedures. The major protein identified as alpha-phosphophoryn had a molecular weight of 153 000 (+/- 5000) and had chromatographic properties similar to those of alpha-phosphophoryn. Since tissue-isolated rat phosphophoryn has a molecular weight of only approximately 90 000 when fully phosphorylated, it appears that the primary gene product is a prepro-alpha-phosphophoryn. Thus, alpha-phosphophoryn in the extracellular space of rat incisor dentin must be the product of one or more posttranslational proteolytic processing steps.

摘要

通过对大鼠上颌切牙（包括牙髓细胞和成牙本质细胞）的总RNA和聚腺苷酸（poly(A+)）mRNA进行无细胞翻译，研究了大鼠切牙牙本质α-磷酸磷蛋白成分的初级基因产物的性质。RNA采用硫氰酸胍法提取，并在兔网织红细胞系统中进行翻译。翻译后的蛋白质通过梯度凝胶电泳进行分析，α-磷酸磷蛋白通过在抗大鼠α-磷酸磷蛋白抗体偶联的琼脂糖柱上分离和斑点印迹法进行鉴定。鉴定为α-磷酸磷蛋白的主要蛋白质分子量为153000（±5000），其色谱性质与α-磷酸磷蛋白相似。由于组织分离的大鼠磷蛋白在完全磷酸化时分子量仅约为90000，因此初级基因产物似乎是前体α-磷酸磷蛋白。因此，大鼠切牙牙本质细胞外空间中的α-磷酸磷蛋白必定是一个或多个翻译后蛋白水解加工步骤的产物。