Expression of galactose genes in mammalian cells. I. Galactose enzymes in Chinese hamster ovary cell hybrids

✍ Scribed by Helene Z. Hill; Meribel B. Halcrow

• Publisher: Springer
• Year: 1972
• Tongue: English
• Weight: 474 KB
• Volume: 7
• Category: Article
• ISSN: 0006-2928
• DOI: 10.1007/bf00486082

✦ Synopsis

Galactokinase and galactose I-phosphate uridyl transferase activities have been studied in several Chinese hamster ovary clonal lines following hybridization of two glycine-requiring mutants. Initially, the hybrids have about twice the parental activity of both enzymes. However, with time, there is a further increase beyond this activity, especially for the transferase enzyme, followed by a decline and a leveling off. The final average kinase activity in the hybrids is about 1.2 times the parental kinase, while the final average transferase is about 1.9 times the parentaI amount. The cultures lose about 10% of their chromosomes during the period under study," however, there is no obvious correlation between gross chromosome loss and enzyme activity. Protein calculated on a per chromosome basis (to correct for chromosome loss) behaves in a manner similar to the enzyme activities. One possible interpretation of the results is that, following hybridization, there is a derepression of some activities followed by repression during which time new levels of cellular parameters become established.