Small Molecule Control of Morpholino Antisense Oligonucleotide Function through Staudinger Reduction

J Am Chem Soc. 2021 Nov 10;143(44):18665-18671. doi: 10.1021/jacs.1c08723. Epub 2021 Oct 27.


Conditionally activated, caged morpholino antisense agents (cMOs) are tools that enable the temporal and spatial investigation of gene expression, regulation, and function during embryonic development. Cyclic MOs are conformationally gated oligonucleotide analogs that do not block gene expression until they are linearized through the application of an external trigger, such as light or enzyme activity. Here, we describe the first examples of small molecule-responsive cMOs, which undergo rapid and efficient decaging via a Staudinger reduction. This is enabled by a highly flexible linker design that offers opportunities for the installation of chemically activated, self-immolative motifs. We synthesized cyclic cMOs against two distinct, developmentally relevant genes and demonstrated phosphine-triggered knockdown of gene expression in zebrafish embryos. This represents the first report of a small molecule-triggered antisense agent for gene knockdown, adding another bioorthogonal entry to the growing arsenal of gene knockdown tools.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Embryo, Nonmammalian / drug effects*
  • Fluorescent Dyes
  • Gene Knockdown Techniques
  • Genes, Developmental
  • Nucleic Acid Conformation
  • Oligonucleotides / chemistry
  • Oligonucleotides, Antisense / chemistry*
  • Oligonucleotides, Antisense / pharmacology*
  • Rhodamines
  • Thionucleotides
  • Zebrafish / embryology


  • Fluorescent Dyes
  • Oligonucleotides
  • Oligonucleotides, Antisense
  • Rhodamines
  • Thionucleotides