Expression studies of CLN3 protein (Battenin) in fusion with the green fluorescent protein in mammalian cells in vitro

The gene for Batten disease, the CLN3 gene, encodes a novel, highly hydroph obic, multitransmembrane protein, predicted to consist of 438 amino acid re sidues. We have expressed a full-length CLN3 protein in fusion with green f luorescent protein in various cell lines to provide its initial biochemical characterization and subcellular localization. By using Western blotting, Percoll density gradient fractionation, and Triton X-114 extraction, we dem onstrate that the product of the CLN3 gene, which we call battenin, in mamm alian expression system studied is a highly glycosylated protein of lysosom al membrane. In addition our data suggest that CLN3 protein is processed pr oteolytically in acidic compartments of the cell. Thus, battenin represents the novel constituent of a growing family of lysosomal membrane proteins. (C) 1999 Academic Press.