DEVELOPMENTAL EXPRESSION OF VGF MESSENGER-RNA IN THE PRENATAL AND POSTNATAL RAT

VGF is a developmentally regulated, secretory peptide precursor that i s expressed by neurons and neuroendocrine cells and that has its trans cription and secretion induced rapidly by neurotrophins and by depolar ization. To gain insight into the possible functions and regulation of VGF in vivo, we have characterized the distribution of VGF mRNA in th e developing rat nervous system. VGF expression was first detectable a t embryonic day 11.5 in the primordia of cranial? sympathetic, and dor sal root ganglia, and its distribution expanded throughout development to include significant expression throughout the brain, spinal cord, and retina of the adult rat. The earliest expression of VGF, therefore , appeared in the peripheral nervous system as developing neurons sett led in their designated ganglia. In many regions of the brain, VGF mRN A levels were found to be highest during periods when axonal outgrowth and synaptogenesis predominate. Areas of the central nervous system t hat contain predominantly dividing cells never displayed any VGF mRNA expression, nor did the vast majority of nonneural tissues. (C) 1998 W iley Liss, Inc.