ISOZYME ANALYSIS OF SOMATIC CELL HYBRIDS: ASSIGNMENT OF THE PHOSPHOGLUCOMUTASE2 (PGM2) GENE LOCUS TO CHROMOSOME 4 IN MAN WITH DATA ON THE MOLECULAR STRUCTURE AND HUMAN CHROMOSOME ASSIGNMENTS OF SIX ADDITIONAL MARKERS

Abstract

ABSTRACT . The analysis of isozyme patterns of lysates of human-rodent somatic cell hybrids provides a convenient method for detecting the presence of human gene products in gene assignment studies and for obtaining data on the molecular structure of these gene products. The expression of human fumarate hydratase (FH) and guanylate kinase (GuK) in Chinese hamster-human somatic cell hybrids was found to be dependent upon the presence of chromosome 1 from man. FH appears to be a tetramer composed for four identical subunits while GuK may exist in monomeric form. Evidence for the monomeric structure of phosphoglucomutase 1 (PGM 1 ) and peptidase C (Pep C) isozymes and for the dimeric structure of 6-phosphogluconate dehydrogenase (PGD) isozymes in man was obtained; PGM 1 , Pep C , and PGD are also chromosome 1 markers in man. Data obtained have provided evidence that the isozymes related to the phosphoglucomutase 2 (PGM 2 ) and to the phosphoglucomutase 3 (PGM 3 ) gene loci in man are monomeric and that the PGM 2 gene locus can be assigned to human chromosome 4. Regional mapping indicates that it can be excluded from the distal portion of the long arm of this chromosome. Further evidence of the dimeric structure of the cytoplasmic form of glutamic oxaloacetic transaminase ( GOT 1 ) was obtained. The tentative assignments of the PGM 3 gene locus to chromosome 6, the gene loci for the cytoplasmic form of GOT and a high Km form of fibroblast hexokinase to chromosome 10 and the gene locus for the dimeric form of superoxide dismutase to chromosome 21 in man have been confirmed.