HUMAN AND RAT OSTEOBLAST-LIKE CELLS EXPRESS STATHMIN, A GROWTH-REGULATORY PROTEIN

We used the differential display polymerase chain reaction method of L iang and Pardee (Science (1992) 257:967-971) to identify a growth-regu latory protein, stathmin or oncoprotein 18, in human and rat osteoblas t-like cells. When messenger ribonucleic acid from human osteosarcoma (Saos-2) cells treated with 10(-8)M 1,25-dihydroxyvitamin D-3 was comp ared with that of cells treated with vehicle alone by this method, we observed an increase in the intensity of a band that on subsequent DNA sequence analysis was found to encode stathmin. We examined normal hu man osteoblast-like cells, transformed human osteoblast-like cells (HO BIT), human osteosarcoma cells (Saos-2), and rat osteoblast cell (ROS 17/2.8, ROS 25/1) lines for the presence of the messenger RNA for stat hmin. All osteoblast-like cells examined expressed the RNA for this pr otein. Western analysis of the protein of these cells with a polyclona l antibody directed against stathmin showed the presence of a M(r) 19, 000 band. We conclude that human and rat osteoblast-like cells express stathmin and that this protein could play a role in regulation of the growth of these cells in response to various hormonal stimuli. (C) 19 94 Academic Press, Inc.