DISTRIBUTION OF CD9 IN THE DEVELOPING AND MATURE RAT NERVOUS-SYSTEM

CD9 is a cell surface protein implicated in intercellular signaling th at has been identified in selected cell types of the hematopoietic sys tem. To begin a study of the role of CD9 in the developing and adult n ervous system, we used the anti-rat CD9 monoclonal antibody ROCA2 to d etermine the distribution of this protein. The identity of the antigen in these tissues was confirmed by immunoblotting and peptide sequenci ng. Early embryonic sympathetic and dorsal root ganglion sensory neuro ns and adrenal chromaffin cells all express CD9. ROCA2 also labels the somas, axons, and growth cones of cultured sympathetic and sensory ne urons. In the central nervous system (CNS), CD9 is transiently and spe cifically expressed in embryonic spinal motorneurons. In the adult, ce ntral and peripheral glia intensely express CD9. Thus, CD9 is developm entally regulated in a variety of peripheral and central neurons and g lia, including proliferating progenitors as well as mature cells. Thes e findings suggest that CD9 may have diverse roles in the nervous syst em. (C) 1993 Wiley-Liss, Inc.