Perturbation of Developmental Regulatory Gene Expression by a G-Quadruplex DNA Inducer in the Sea Urchin Embryo

The G-quadruplex (G4) is a four-stranded DNA structure identified in vivo in guanine-rich regions located in the promoter of a number of genes. Intriguing evidence suggested that small molecules acting as G4-targeting ligands could potentially regulate multiple cellular processes via either stabilizing or disruptive effects on G4 motifs. Research in this field aims to prove the direct role of G4 ligands and/or structures on a specific biological process in a complex living organism. In this study, we evaluate in vivo the effects of a nickel(II)-salnaphen-like complex, named Nisaln, a potent G4 binder and stabilizer, during embryogenesis of the sea urchin embryo. We describe developmental defects inflicted by Nisaln and correlate them with variation in the expression of several regulatory genes. It is worth mentioning that we show that Nisaln binds a G4 structure in the promoter of hbox12-a, a gene lying at the top of the developmental regulatory hierarchy, inducing overexpression of this gene.