Expression and localization of utrophin in differentiating PC12 cells.

To ascertain the role of utrophin in cultured neuronal cells, we investigated its expression and distribution along the NGF-induced differentiation of PC12 cells grown on different substrata. Utrophin mRNA was measured by RT-PCR assay and utrophin protein was quantified by immunoblot analysis. The distribution of utrophin and beta-dystroglycan was analyzed by confocal microscopy. We demonstrate that utrophin protein was increased 4-fold during differentiation of cells grown laminin. Concomitant with this up-regulation, utrophin was enriched at the growth cones in differentiating cells, where it co-localizes with beta-dystroglycan. These data suggest the presence of a utrophin-beta-dystroglycan complex in PC12 cells that participates in the formation and/or stabilization of the growth cone-extracellular matrix adhesion.