GM1-GANGLIOSIDOSIS - CHROMOSOME-3 ASSIGNMENT OF THE BETA-GALACTOSIDASE-A GENE (BETA-GALA)

The structural gene (βGALA) coding for lysosomal β-galactosidase- A (EC 3.2.1.23) has been assigned to human chromosome 3 using man-mouse somatic cell hybrids. Human β-galactosidase-A was identified in cell hybrids with a species-specific antiserum to human liver β-galactosidase-A. The antiserum precipitates β-galactosidase-A from human tissues, cultured cells, and cell hybrids, and recognizes cross-reacting material from a patient with GM1 gangliosidosis. We have analyzed 90 primary man-mouse hybrids derived from 12 separate fusion experiments utilizing cells from 9 individuals. Enzyme segregation analysis excluded all chromosomes for βGALA assignment except chromosome 3. Concordant segregation of chromosomes and enzymes in 16 cell hybrids demonstrated assignment of βGALA to chromosome 3; all other chromosomes were excluded. The evidence suggests that GM1 gangliosidosis is a consequence of mutation at this βGALA locus on chromosome 3. © 1979 Plenum Publishing Corporation.