title: Characterization of the primary gene product of rat incisor alpha-phosphophoryn.
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.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D005796:Genes; D007180:Incisor / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D010750:Phosphoproteins / Q000235:genetics* / Q000302:isolation & purification; D014176:Protein Biosynthesis; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D012156:Reticulocytes / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010750:Phosphoproteins; C017630:phosphophoryn