Expression of the extra-large G protein alpha-subunit XL alpha s in neuroepithelial cells and young neurons during development of the rat nervous system

XL alphas ('extra large' alpha) is a 78 kDa splice variant of the alpha -su bunit of the heterotrimeric G protein, Gs (Nature 372 (1994) 804). Prompted by its neuroendocrine-specific tissue distribution in the adult (J. Biol, Chem. 275 (2000) 33622) and its ability to activate adenylyl cyclase (J. Bi ol. Chem. 275 (2000) 33633), we investigated the expression of XL alphas in the developing rat nervous system using immunofluorescence. Remarkably, XL alphas expression in the neural tube was found to begin at the onset of ne urogenesis, being observed in a subset of mitotic neuroepithelial cells as well as in young neurons. At later developmental stages, XL alphas was asso ciated with a subset of neurons in certain regions of the nervous system su ch as diencephalon, midbrain, hindbrain, spinal cord and sympathetic trunk. These results suggest a role of XL alphas in neuronal differentiation. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.