The association of glucose phosphate isomerase expression with human chromosome 19 using somatic cell hybrids

Abstract

Clones of two Chinese hamster human hybrid somatic cell lines were studied for the presence or absence of human glucose phosphate isomerase (GPI; E.C.5.3.1.9). Quinacrine mustard fluorescence was used for chromosome identification. Clones from one line could be separated into five separate classes. These are considered to represent four different nondisjunctional events. Since it is the number of non-disjunctional events which is important and not the number of clones, two representative clones from each class were analyzed. The classes were: (I) identical to parental hybrid; (II) loss of chromosome 14; (III) loss of chromosome 1; (IV) loss of chromosomes 1 and 19; and (V) loss of chromosomes 1 and 11. Concomitantly, the following human enzymes were lost; (I) none; (II) NP; (III) PGM1 and 6PGD; (IV) PGM1, 6PGD, and GPI; and (V) PGMi, 6PGD, and LDH-B. In the second hybrid line only two types of clones were observed, GPI+ and GPI–. The two GPI– clones analyzed had also lost chromosome 19. We believe the most likely explanation for these results to be the presence of the GPI structural locus on human chromosome 19. Data from these two lines also supports association of PGM1 and 6PGD with chromosome 1, of NP with chromosome 14, and LDH-B with chromosome 12.