Adjusting the Cellular Clock

Source: Orlando et al. (2008). Global control of cell-cycle transcription by coupled CDK and network oscillators. Nature 453:944-947.

This short paper highlights the fact that the periodicity observed in the expression of many genes across the cell cycle, although initially attributed to the CDKs, is in fact additionally controlled by a transcription network. Their basic observation is that in a cyclin-mutant cell, the periodic expression of the genes, although aberrant, is largely intact; whereas, the cells are arrested in the G1-S transition.

Their results suggest a transcription network in which the transcription factors are sequentially activated in a cyclic manner as an independent clock based on which the cell determines its progression in the cell cycle. This apparent redundancy (i.e. the presence of two oscillators) in this system ensures the robustness of the cell cycle regulation in our cells.