Quiescent cells in vitro have very low levels expression of the transcription factor c-Myc. Its up-regulation is rapidly induced after mitogenic stimulation or the introduction of serum and increased expression of c-Myc is consistent with the advancement of cellular proliferation [41] . Control of myc transcription can be influenced by a number of pathways, including PI3K/Akt signalling, which was shown here to occur as a result of binding by gD. A central role for c-Myc in promoting cell-cycle progression is evident from the genes that it can up-regulate such as eIF2 [42] . Progression of the cell cycle depends on the additional activity of cyclin-dependent kinases. By interacting with the promoters for genes encoding cyclins and cyclin-dependent kinases, c-Myc can influence the advancement on the cell cycle into the G1/S phase [43] .