CONTROL OF SEGMENT-LIKE PATTERNS OF GENE-EXPRESSION IN THE MOUSE CEREBELLUM

A Purkinje cell-specific transgene, L7-lacZ, is expressed in a series of parasagitally oriented stripes in the mouse cerebellum. This bandin g pattern can be perturbed by promoter mutation, showing that a combin ation of positive and negative control elements contributes to the tem poral and spatial map of L7 gene expression. In addition to the parasa gittal stripes, certain mutations reveal Purkinje cells organized into compartments oriented in the transverse plane of the cerebellum. Tran scription factors of the POU or homeobox families appear to be involve d in controlling L7 expression in the transverse orientation. Striking ly, some of the domains of gene expression revealed by the mutations a ppear to correspond to functional compartments of Purkinje cells, ther eby suggesting an underlying genetic principle used to orchestrate fun ctional organization in the nervous system.