Figure 1.

Delta-24-RGD harbors a 24-base pair deletion in the viral E1A region that is responsible for binding Retinoblastoma (Rb), and contains the inserted RGD sequence to enhance infectivity (Figure 1A). Rb protein normally prevents cells from entering S-phase. Because E1A is mutated, the virus is unable to replicate in cells that have functioning Rb, i.e. normal cells. However, the virus is able to replicate in cells that have lost or mutated Rb protein, i.e. tumor cells (Figure 1B).