NOVEL RECEPTOR PROTEIN-TYROSINE-PHOSPHATASE (RPTP-RHO) AND ACIDIC FIBROBLAST GROWTH-FACTOR (FGF-1) TRANSCRIPTS DELINEATE A ROSTROCAUDAL BOUNDARY IN THE GRANULE CELL LAYER OF THE MURINE CEREBELLAR CORTEX

We have identified a novel receptor-like protein tyrosine phosphatase (RPTP rho) transcript whose expression in the cerebellar cortex is res tricted to the granule cell layer of lobules 1-6. Acidic fibroblast gr owth factor (FGF-1) mRNA follows a similar cerebellar expression patte rn. Together, the two markers define a sharp boundary in lobule 6, sli ghtly caudal to the primary fissure. Anterior and posterior compartmen ts became discernible only during postnatal weeks two and six, for RPT P rho and FGF-1, respectively. A rostrocaudal boundary in lobule 6 of the murine cerebellar cortex has also been identified morphologically by the effects of the meander tail mutation. The position of the RPTP rho and FGF-1 boundary on the rostrocaudal axis of the cerebellar cort ex was close to, but not coincident with, the caudal extent of the dis organized anterior lobe of meander tail and the rostral extent of Otx- 2 expression. The restricted pattern of FGF-1 and RPTP rho implies tha t these molecules may have specific signaling roles in the tyrosine ph osphorylation/dephosphorylation pathway in the anterior compartment of the adult cerebellar cortex. (C) 1998 Wiley-Liss, Inc.