HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Cover picture: Image taken from a coronal slice of embryonic day 17 (E17) rat cortex. The cortex had been pulsed with 5-bromo-2'-deoxyuridine (BrdU) for 1 hr before fixing the tissue. BrdU (green) labels the mitotically active precursor cells (including neuronal progenitors) that are located in the ventricular zone of the developing rat cortex at this age. The tissue was then counterstained with the membranous marker concanavalin A (blue) to identify individual cells. Inset, A small cluster of green fluorescent protein (GFP)-labeled cells (green) in the cortical plate that may be clonally related. These cells had been labeled with a GFP reporter gene through an intraventricular injection, in utero, of a GFP-expressing retrovirus at E16, and were allowed to survive until E20. The retrovirus infects only mitotically active precursor cells in the ventricular zone, and the retrovirus is replication incompetent, so that only the precursor cell and its progeny carry the reporter gene. The tissue was counterstained with an antibody to nestin that labels neuronal precursor cells in the ventricular zone as well as the radial fibers of these cells, which course through the cortical plate to the pial surface. This figure illustrates that mitotically active neuronal precursor cells in the ventricular zone generate neurons that migrate into the cerebral cortex. The neuronal precursor cells have now been identified as radial glia. For details, see the article by Noctor et al. in this issue (pages 3161-3173).