Ruthenium-caged antisense morpholinos for regulating gene expression in zebrafish embryos†

Abstract

Ruthenium photolinkers provide a versatile method of using visible light to control structure and function of biopolymers.

Abstract

Photochemical approaches afford high spatiotemporal control over molecular structure and function, for broad applications in materials and biological science. Here, we present the first example of a visible light responsive ruthenium-based photolinker, Ru(bipyridine) ₂(3-ethynylpyridine) ₂ (RuBEP), which was reacted stoichiometrically with a 25mer DNA or morpholino (MO) oligonucleotide functionalized with 3′ and 5′ terminal azides, via Cu( i)-mediated [3+2] Huisgen cycloaddition reactions. RuBEP-caged circular morpholinos (Ru-MOs) targeting two early developmental zebrafish genes, chordin and notail, were synthesized and tested in vivo. One-cell-stage zebrafish embryos microinjected with Ru-MO and incubated in the dark for 24 h developed normally, consistent with caging, whereas irradiation at 450 nm dissociated one 3-ethynylpyridine ligand ( Φ = 0.33) and uncaged the MO to achieve gene knockdown. As demonstrated, Ru photolinkers provide a versatile method for controlling structure and function of biopolymers.

Notes

†Electronic supplementary information (ESI) available: Synthetic protocols and characterization data for RuBEP, Ru–DNA and Ru-MO, purification and injection protocols, and oligo sequences. CCDC 1041125. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4sc03990d