Polyamine starvation prolongs the S and G2 phases of polyamine-dependent (arginase-deficient) CHO cells.

AUTOR(ES)

Anehus, S

RESUMO

This study analyzes the effects of polyamine starvation on cell cycle traverse of an arginase-deficient CHO cell variant (CHO-A7). These cells grow well in serum-free medium, provided that it contains ornithine or polyamines or both. In the absence of ornithine or polyamines or both, the CHO-A7 cells develop severe polyamine deficiency and, as a consequence, grow more slowly. When grown to a stationary phase in the presence of ornithine or putrescine or both, the CHO-A7 cells became arrested in G0/early G1. However, when starved for ornithine and polyamines, they accumulated in the S and G2 phases. Ornithine and polyamine starvation of CHO-A7 cells causes an increase in ornithine decarboxylase activity. When this increase was prevented by treatment with DL-alpha-difluoromethylornithine, an enzyme-activated irreversible inhibitor of ornithine decarboxylase, growth was further suppressed, and a greater fraction of cells were found in the S and G2 phases of the cell cycle.

Documentos Relacionados

• Phosphorylation of ornithine decarboxylase by a polyamine-dependent protein kinase.
• Structural elements of ornithine decarboxylase required for intracellular degradation and polyamine-dependent regulation.
• Neurospora Mutants Affecting Polyamine-Dependent Processes and Basic Amino Acid Transport Mutants Resistant to the Polyamine Inhibitor, α-Difluoromethylornithine
• Human cyclin-dependent kinase 2 is activated during the S and G2 phases of the cell cycle and associates with cyclin A.
• G2 phase-specific proteins of HeLa cells.