While much is known about how dNTP concentrations are achieved and maintained during different phases of the cell cycle or after DNA damage, it remains largely unknown if the changes in dNTP concentration have a direct role in the regulation of cell cycle progression, apoptosis and other processes. The increase in dNTP concentration after DNA damage, which is crucial for survival in yeast, suggests that such regulatory roles do exist.
The dNTP concentration-dependent regulation of DNA replication origin firing (the early replication origins fire even when dNTP pools are depleted, while the late origins do not) is another indication that dNTPs have regulatory functions and are not merely the DNA building blocks. Importantly, a number of proteins (including Apaf-1, a key regulator of apoptosis, and RecA, a protein involved in DNA recombination) have been demonstrated to bind dNTPs several orders of magnitude better than the corresponding NTPs. The biochemical activity of these proteins is stimulated by dNTPs at much lower concentrations compared to the corresponding NTPs, although the physiological role of the preferential dNTP binding and stimulation is not known.
Using a broad genetic and biochemical approach, we will systematically identify novel dNTP-binding proteins and dNTP-regulated processes and investigate the role of dNTPs in the control of cell cycle, replication origin firing and apoptosis.
