A Conserved Splicing Silencer Dynamically Regulates O-GlcNAc Transferase Intron Retention and O-GlcNAc Homeostasis

Cell Rep. 2017 Aug 1;20(5):1088-1099. doi: 10.1016/j.celrep.2017.07.017.

Abstract

Modification of nucleocytoplasmic proteins with O-GlcNAc regulates a wide variety of cellular processes and has been linked to human diseases. The enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) add and remove O-GlcNAc, but the mechanisms regulating their expression remain unclear. Here, we demonstrate that retention of the fourth intron of OGT is regulated in response to O-GlcNAc levels. We further define a conserved intronic splicing silencer (ISS) that is necessary for OGT intron retention. Deletion of the ISS in colon cancer cells leads to increases in OGT, but O-GlcNAc homeostasis is maintained by concomitant increases in OGA protein. However, the ISS-deleted cells are hypersensitive to OGA inhibition in culture and in soft agar. Moreover, growth of xenograft tumors from ISS-deleted cells is compromised in mice treated with an OGA inhibitor. Thus, ISS-mediated regulation of OGT intron retention is a key component in OGT expression and maintaining O-GlcNAc homeostasis.

Keywords: O-GlcNAc; O-GlcNAc homeostasis; O-GlcNAc transferase; OGA; OGT; OSMI-1; RNA splicing; intron retention; splicing silencer; thiamet-G.

Publication types

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

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Humans
  • Introns*
  • Mice
  • N-Acetylglucosaminyltransferases* / biosynthesis
  • N-Acetylglucosaminyltransferases* / genetics
  • Neoplasms, Experimental* / genetics
  • Neoplasms, Experimental* / metabolism
  • Neoplasms, Experimental* / pathology
  • RNA Splicing*

Substances

  • N-Acetylglucosaminyltransferases
  • O-GlcNAc transferase