Regulation of transcription termination by glucosylated hydroxymethyluracil, base J, in Leishmania major and Trypanosoma brucei

Nucleic Acids Res. 2014 Sep;42(15):9717-29. doi: 10.1093/nar/gku714. Epub 2014 Aug 7.


Base J, β-d-glucosyl-hydroxymethyluracil, is an epigenetic modification of thymine in the nuclear DNA of flagellated protozoa of the order Kinetoplastida. J is enriched at sites involved in RNA polymerase (RNAP) II initiation and termination. Reduction of J in Leishmania tarentolae via growth in BrdU resulted in cell death and indicated a role of J in the regulation of RNAP II termination. To further explore J function in RNAP II termination among kinetoplastids and avoid indirect effects associated with BrdU toxicity and genetic deletions, we inhibited J synthesis in Leishmania major and Trypanosoma brucei using DMOG. Reduction of J in L. major resulted in genome-wide defects in transcription termination at the end of polycistronic gene clusters and the generation of antisense RNAs, without cell death. In contrast, loss of J in T. brucei did not lead to genome-wide termination defects; however, the loss of J at specific sites within polycistronic gene clusters led to altered transcription termination and increased expression of downstream genes. Thus, J regulation of RNAP II transcription termination genome-wide is restricted to Leishmania spp., while in T. brucei it regulates termination and gene expression at specific sites within polycistronic gene clusters.

Publication types

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

MeSH terms

  • Cell Line
  • Gene Expression Regulation*
  • Glucosides
  • Leishmania major / enzymology
  • Leishmania major / genetics*
  • RNA Polymerase II / metabolism
  • RNA, Protozoan / analysis
  • Transcription Termination, Genetic*
  • Trypanosoma brucei brucei / enzymology
  • Trypanosoma brucei brucei / genetics*
  • Uracil / analogs & derivatives*
  • Uracil / physiology


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

Associated data

  • GEO/GSE57621