Accepted

Transgenic mice were used as an assay system for the isolation and characterization of the promoter for cerebroglycan, a neural-specific cell surface proteoglycan expressed during the period of axon extension and guidance. A nuclear-localized P-galactosidase reporter gene was fused to a segment of upstream cerebroglycan genomic DNA and used to create several transgenic mice through pronuclear injection. These mice were stained for transgene expression patterns using X-gal, a chromogenic substrate for P-galactosidase. Nine out of eleven transgenic mice possessed nearly identical staining patterns which were neural-specific and similar, but not identical to the pattern of cerebroglycan expression. The promoter fragment was sequenced and was found to have significant homologies to the promoter for another neural-specific gene, Ta 1. The isolated promoter may be useful for the study of neural-specific gene regulation and for the study of neural development by providing the means of expressing exogenous genes in a unique pattern during axon growth and guidance. Several independent strains of transgenic mice were created which greatly facilitate th