Activatable Photosensitizer for Targeted Ablation of <i>lacZ</i>-Positive Cells with Single-Cell Resolution

Abstract

To achieve highly selective ablation of <i>lacZ</i>-positive cells in a biological milieu <i>in vivo</i>, we developed an activatable photosensitizer, SPiDER-killer-βGal, targeted to β-galactosidase encoded by the <i>lacZ</i> reporter gene. Hydrolysis of SPiDER-killer-βGal by β-galactosidase simultaneously activates both its photosensitizing ability and its reactivity to nucleophiles, so that the phototoxic products generated by light irradiation are trapped inside the <i>lacZ</i>-positive cells. The combination of SPiDER-killer-βGal and light irradiation specifically killed <i>lacZ</i>-positive cells in coculture with cells without <i>lacZ</i> expression. Furthermore, β-galactosidase-expressing cells in the posterior region of cultured <i>Drosophila</i> wing discs and in pupal notum of live <i>Drosophila</i> pupae were selectively killed with single-cell resolution. This photosensitizer should be useful for specific ablation of targeted cells in living organisms, for example, to investigate cellular functions in complex networks.