Glucosylated hydroxymethyluracil, DNA base J, prevents transcriptional readthrough in Leishmania

Cell. 2012 Aug 31;150(5):909-21. doi: 10.1016/j.cell.2012.07.030.


Some Ts in nuclear DNA of trypanosomes and Leishmania are hydroxylated and glucosylated to yield base J (β-D-glucosyl-hydroxymethyluracil). In Leishmania, about 99% of J is located in telomeric repeats. We show here that most of the remaining J is located at chromosome-internal RNA polymerase II termination sites. This internal J and telomeric J can be reduced by a knockout of J-binding protein 2 (JBP2), an enzyme involved in the first step of J biosynthesis. J levels are further reduced by growing Leishmania JBP2 knockout cells in BrdU-containing medium, resulting in cell death. The loss of internal J in JBP2 knockout cells is accompanied by massive readthrough at RNA polymerase II termination sites. The readthrough varies between transcription units but may extend over 100 kb. We conclude that J is required for proper transcription termination and infer that the absence of internal J kills Leishmania by massive readthrough of transcriptional stops.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Gene Knockout Techniques
  • Glucosides / metabolism*
  • Leishmania / genetics*
  • Leishmania / metabolism*
  • RNA Polymerase II / metabolism
  • RNA, Double-Stranded / metabolism
  • Transcription, Genetic*
  • Uracil / analogs & derivatives*
  • Uracil / metabolism


  • Glucosides
  • RNA, Double-Stranded
  • 5-((glucopyranosyloxy)methyl)uracil
  • Uracil
  • RNA Polymerase II

Associated data

  • GEO/GSE32976