THE BEIGE CHEDIAK-HIGASHI-SYNDROME GENE ENCODES A WIDELY EXPRESSED CYTOSOLIC PROTEINS/

The human autosomal recessive disorder Chediak-Higashi syndrome and it s murine homologue beige are associated with the formation of giant ly sosomes that cluster near the perinuclear region of cells, We prepared a polyclonal antiserum against a glutathione S-transferase-Beige fusi on protein and demonstrated by Western analysis that the beige gene en codes a protein of 400 kDa that is expressed in cultured murine fibrob lasts as well as most mouse tissues, The protein was not detected in e ither cultured fibroblasts or mouse tissues from two different beige m utants, Cultured fibroblasts transformed with multiple copies of yeast artificial chromosomes that contain the full-length beige gene showed much higher levels of Beige protein than either wild type fibroblasts or mouse tissues. Subcellular fractionation experiments demonstrated that the Beige protein was cytosolic and, under the conditions of isol ation, had no measurable membrane association, Cultured mouse fibrobla sts in which the Beige protein was overexpressed had smaller than norm al lysosomes that were more peripherally distributed than in control c ells, These findings, coupled with earlier published results, suggest that the Beige protein regulates lysosomal fission.