Changes in OL cell cycle proteins in 1% O₂.

<p>Whole cell lysates from OLs cultured at 21% O₂ or 1% O₂ in the presence or absence of GFs, were analyzed by immunoblot analysis for phosphorylation state of cell cycle proteins Rb and cdc2, and for the negative regulator of cell cycle, p27^Kip1. Ribosomal S6 protein was used as a loading control. The approximate sizes for Rb, cdc-2, p27^Kip1 and ribosomal S6 protein are 110 kDa, 34 kDa, 27 kDa and 32 kDa, respectively. Representative Western blot from 3 different preparations shows an increase in phosphorylated forms of Rb and cdc-2, and total p27^Kip1 levels in hypoxia. Data shown are representative of three separate studies.