Detection of active heteropolymeric beta-glucuronidase in hybrids between mouse cells and human fibroblasts with beta-glucuronidase deficiency.

Heteropolymeric beta-glucuronidases are detected in somatic cell hybrids between mouse cells and human fibroblasts deficient in beta-glucuronidase (beta-D-glucuronide glucuronosohydrolase, EC 3.2.1.31) by electrophoresis and column chromatography. Specific antisera against human beta-glucuronidase prepared in mice recognize these heteropolymeric beta-glucuronidases. Our results demonstrate that synthesis of mutant subunits of variant beta-glucuronidase continues in deficient human fibroblasts; these mutant subunits of human beta-glucuronidase retain the ability to associate with normal subunits of mouse beta-glucuronidase to form the enzymatically and immunologically active tetramer. These studies demonstrate the usefulness of interspecific cell hybrids for study of structural gene mutations of polymeric enzymes, such as those of beta-glucuronidase in mucopolysaccharidosis type VII.