The receptor protein tyrosine phosphatase mu, PTPμ, regulates histogenesis of the chick retina

The formation of laminae within the retina requires the coordinate regulation of cell differentiation and migration. The cell adhesion molecule and member of the immunoglobulin superfamily, receptor protein tyrosine phosphatase Mu, PTPmu, is expressed in precursor and early, differentiated cells of the prelaminated retina, and later becomes restricted to the inner plexiform, ganglion cell, and optic fiber layers. Since the timing of PTPmu expression correlates with the peak period of retinal lamination, we examined whether this RPTP could be regulating cell adhesion and migration within the retina, and thus influencing retinal development. Chick retinal organ cultures were infected with herpes simplex viruses encoding either an antisense sequence to PTPmu, wild-type PTPmu, or a catalytically inactive mutant form of PTPmu, and homophilic adhesion was blocked by using a function-blocking antibody. All conditions that perturbed PTPA dramatically disrupted retinal histogenesis. Our findings demonstrate that catalytic activity and adhesion mediated by PTPmu regulate lamination of the retina, emphasizing the importance of adhesion and signaling via receptor protein tyrosine phosphatases in the developing nervous system. To our knowledge, this is the first demonstration that an Ig superfamily RPTP regulates the lamination of any neural tissue. (C) 2003 Elsevier Inc. All rights reserved.