GOLLI-MBP PROTEINS MARK THE EARLIEST STAGES OF FIBER EXTENSION AND TERMINAL ARBORATION IN THE MOUSE PERIPHERAL NERVOUS-SYSTEM

The Golli-myelin basic protein (MBP) transcription unit gives rise to two sets of products. One set (i.e., the MBPs) is expressed exclusivel y in myelin forming cells and the other set (i.e., the golli isoforms) is expressed in both oligodendrocytes and neurons in the CNS. The two major golli proteins, generated from RNAs transcribed from the most u pstream promoter of the gene, contain MBP peptide sequences in their C -terminal halves and are, therefore, structurally and immunologically related to the MBPs, We have examined the distribution and localizatio n of golli proteins in the mouse peripheral nervous system (PNS) using immunocytochemistry with a golli-specific antibody. Golli immunoreact ivity was first observed in sensory and motor fibers of the mouse at E 11 during fiber tract extension, but prior to the maturation of termin al connections, Once neuromuscular junctions had formed, golli immunor eactivity appeared in motor endplates and persisted to the latest age examined, P60. Golli immunoreactivity was also observed in the cell bo dies and processes of the dorsal root ganglia throughout development, Strong staining in the PNS of the dysmyelinating mutant shiverer sugge sted that the major golli protein in peripheral fibers was the BG21 is oform, Interestingly, golli immunoreactivity was also found in adrenal chromaffin cells, which share a common neural crest derivation with o ther postganglionic neurons that express golli protein, These results suggest that in addition to its role in early forming neuronal systems of the CNS, golli protein also plays a role in the early development and maintenance of neurons in the PNS. (C) 1997 Wiley-Liss, Inc.