Phosphorothioate antisense oligonucleotides induce the formation of nuclear bodies

Mol Biol Cell. 1998 May;9(5):1007-23. doi: 10.1091/mbc.9.5.1007.

Abstract

Antisense oligonucleotides are powerful tools for the in vivo regulation of gene expression. We have characterized the intracellular distribution of fluorescently tagged phosphorothioate oligodeoxynucleotides (PS-ONs) at high resolution under conditions in which PS-ONs have the potential to display antisense activity. Under these conditions PS-ONs predominantly localized to the cell nucleus where they accumulated in 20-30 bright spherical foci designated phosphorothioate bodies (PS bodies), which were set against a diffuse nucleoplasmic population excluding nucleoli. PS bodies are nuclear structures that formed in cells after PS-ON delivery by transfection agents or microinjection but were observed irrespectively of antisense activity or sequence. Ultrastructurally, PS bodies corresponded to electron-dense structures of 150-300 nm diameter and resembled nuclear bodies that were found with lower frequency in cells lacking PS-ONs. The environment of a living cell was required for the de novo formation of PS bodies, which occurred within minutes after the introduction of PS-ONs. PS bodies were stable entities that underwent noticeable reorganization only during mitosis. Upon exit from mitosis, PS bodies were assembled de novo from diffuse PS-ON pools in the daughter nuclei. In situ fractionation demonstrated an association of PS-ONs with the nuclear matrix. Taken together, our data provide evidence for the formation of a nuclear body in cells after introduction of phosphorothioate oligodeoxynucleotides.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antigens / metabolism
  • Cell Nucleus / drug effects*
  • Cell Nucleus / ultrastructure
  • HeLa Cells
  • Humans
  • Intracellular Fluid
  • Nuclear Matrix / metabolism
  • Oligonucleotides, Antisense / metabolism
  • Oligonucleotides, Antisense / pharmacology*
  • Thionucleotides / metabolism
  • Thionucleotides / pharmacology*

Substances

  • Antigens
  • Oligonucleotides, Antisense
  • Thionucleotides