Figure 4.

Cell cycle effects and neurite extension caused by NGF addition. (A) PC12 cells transfected with both the G₁ phase biosensor (left) and a plasma membrane marker (Kras tail) (right) were imaged to identify cell cycle phases and neurite extensions, respectively. PC12 cells expressing the G₁ phase biosensor and Kras tail were cultured in media containing serum (B) or serum-free media (C) for 24 hours and then cultured in media containing serum + NGF (Control) or NGF. Schematics of the experimental designs are located above the graphs of the corresponding data. Panels on the left give the percent of PC12 cells in G₁ phase, i.e., those with a nuclear-localized G₁ phase biosensor. The middle panels indicate the percent of cells with plasma membrane extensions (neurites) at least 1.5 × their body diameter. Combining the information from the G₁ phase biosensor and the Kras tail allows for the assignment of either G₁ phase or S/G₂ phases to the cells that have formed neurites (panels on the right). Error bars are 95% confidence intervals.