Cdk2 activity is dispensable for triggering replicon initiation after transient hypoxia in T24 cells.

We examined whether the fast release of replicon initiation after sudden O2 recovery of hypoxically incubated mammalian cells depends on kinase activity of Cdk2. We used a system based on starved/refed T24 cells elaborated previously for such investigations [van Betteraey-Nikoleit M, Eisele KH, Stabenow D and Probst H (2003) Eur J Biochem270, 3880-3890]. Cells subjected to hypoxia concurrently with refeeding accumulate the G1 DNA content within 5-6 h.

Analyzing changes of chromatin-bound replication proteins occurring in response to and after release from a hypoxic block of replicon initiation in T24 cells.

It was shown previously [Riedinger, H. J., van Betteraey-Nikoleit, M & Probst, H.

Re-oxygenation of hypoxic simian virus 40 (SV40)-infected CV1 cells causes distinct changes of SV40 minichromosome-associated replication proteins.

Hypoxia interrupts the initiation of simian virus 40 (SV40) replication in vivo at a stage situated before unwinding of the origin region. After re-oxygenation, unwinding followed by a synchronous round of viral replication takes place. To further characterize the hypoxia-induced inhibition of unwinding, we analysed the binding of several replication proteins to the viral minichromosome before and after re-oxygenation.