IN-VIVO TRANSFER OF A MARKER GENE TO STUDY MOTONEURONAL DEVELOPMENT

ADENOVIRUS vectors containing a marker gene (lacZ from Escherichia col i) are potent for transferring the gene to neurones after intraparench ymal injections. Expression of the marker gene may lead to the synthes is of an enormous amount of beta-galactosidase which diffuses througho ut the entire neurone, providing a 'Golgi-like' staining. This suggest ed that the technique may be used to study the morphology of specific neuronal populations. We have validated this hypothesis by analysing t he postnatal development of motoneurones in the rat cervical cord. Inj ections of the viral suspension into one ventral horn were performed a t different ages after birth. Histochemical staining using X-Gal revea led morphological changes occurring within the first 3 weeks with enla rgement of the perikaryon and increased dendritic complexity. Immunore activity for CGRP was visualized in double-staining experiments. In vi vo transfer of a marker gene therefore provides a new way to analyse n euronal morphology which allows selection of the cells to be studied a nd double-labelling with immunohistochemical markers.