Phospholipase Cbeta4 expression reveals the continuity of cerebellar topography through development.

Mediolateral boundaries divide the mouse cerebellar cortex into four transverse zones, and within each zone the cortex is further subdivided into a symmetrical array of parasagittal stripes. Various expression markers reveal this complexity, and detailed maps have been constructed based on the differential expression of zebrin II/aldolase C in a Purkinje cell subset. Recently, phospholipase (PL) Cbeta4 expression in adult mice was shown to be restricted to, and coextensive with, the zebrin II-immunonegative Purkinje cell subset. The Purkinje cell expression of PLCbeta4 during embryogenesis and postnatal development begins just before birth in a subset of Purkinje cells that are clustered to form a reproducible array of parasagittal stripes. Double label and serial section immunocytochemistry revealed that the early PLCbeta4-immunoreactive clusters in the neonate are complementary to those previously identified by neurogranin expression. The PLCbeta4 expression pattern can be traced continuously from embryo to adult, revealing the continuity of the topographical map from perinatal to adult cerebella. The only exception, as has been seen for other antigenic markers, is that transient PLCbeta4 expression (which subsequently disappears) is seen in some Purkinje cell stripes during the second postnatal week. Furthermore, the data confirm that some adult Purkinje cell stripes are composite in origin, being derived from two or more distinct embryonic clusters. Thus, the zone and stripe topography of the cerebellum is conserved from embryo to adult, confirming that the early- and late-antigenic markers share a common cerebellar topography.