DEVELOPMENTAL REGULATION OF THY-1.2 RATE OF SYNTHESIS IN THE MOUSE CEREBELLUM

Thy 1.2 is a well-known major cell surface glycoprotein of the central nervous system (CNS), However, the regulation of the expression of th is molecule as well as its function are yet to be determined, To appro ach these problems we studied the synthesis of the molecule in the dev eloping cerebellum of wild-type and staggerer mutant mice, We found th e appearance of a [S-35]-methionine-labeled band detected with specifi c Sepharose 4B-bound monoclonal antibodies (Mabs), The Thy 1.2 activit y increases progressively from postnatal day 9 (P9), reaching the high est rate at P12, subsequently decreasing sharply at P13, and remaining relatively low up to P16 in the wild type, Comparison of these data t o the rates of total protein synthesis reveals a selective development al regulation of Thy 1.2 expression, at least at the translational lev el. This correlates quite well with the timing of synaptic stabilizati on between parallel fibers and Purkinje cell dendritic spines, Further more, at P12 Thy 1.2 protein is preferentially located in the synaptos omal fraction, The parallel fiber:Purkinje cell synapsis is not stabil ized in the staggerer mutant mouse, At P12 Thy 1.2 synthesis is 30% of the wild type, indicating that the translational regulation of Thy 1. 2 is altered in the staggerer mutation. (C) 1995 Wiley-Liss, Inc.