Premium
EMA: A developmentally regulated cell‐surface glycoprotein of CNS neurons that is concentrated at the leading edge of growth cones
Author(s) -
Baumrind Nikki L.,
Parkinson David,
Wayne Denise B.,
Heuser John E.,
Pearlman Alan L.
Publication year - 1992
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/aja.1001940407
Subject(s) - biology , microbiology and biotechnology , glycoprotein , cell , growth cone , neuroscience , biochemistry , axon
To identify cell‐surface molecules that mediate interactions between neurons and their environment during neural development, we used monoclonal antibody techniques to define a developmentally regulated antigen in the central nervous system of the mouse. The antibody we produced (2A1) immunolabels cells throughout the central nervous system; we analyzed its distribution in the developing cerebral cortex, where it is expressed on cells very soon after they complete mitosis and leave the periventricular proliferative zone. Expression continues into adult life. The antibody also labels the epithelium of the choroid plexus and the renal proximal tubules, but does not label neurons of the peripheral nervous system in the dorsal root ganglia. In dissociated cell culture of embryonic cerebral cortex, 2A1 labels the surface of neurons but not glia. Immunolabeling of neurons in tissue culture is particularly prominent on the edge of growth cones, including filopodia and the leading edge of lamellipodia, when observed with either immunofluorescence or freeze‐etch immunoelectron microscopy. Immunopurification with 2A1 of a CHAPS‐extracted membrane preparation from brains of neonatal mice produces a broad (32–36 kD) electrophoretic band and a less prominent 70 kD band that are sensitive to N‐glycosidase but not endoglycosidase H. Thus the 2A1 antibody recognizes a developmentally regulated, neuronal cell surface glycoprotein (or glycoproteins) with complex N‐linked oligosaccharide side chains. We have termed the glycoprotein a ntigen EMA because of its prominence on the e dge m embrane of growth cones. EMA is similar to the M6 antigen (Lagenaur et al: J. Neurobiol. 23:71–88, 1992) in apparent molecular weight, distribution in tissue sections, and immunoreactivity on Western blots, suggesting that the two antigens are similar or identical. Expression of EMA is a very early manifestation of neuronal differentiation; its distribution on growth cones suggests a role in mediating the interactions between growth cones and the external cues that guide them. © 1992 Wiley‐Liss, Inc.