Two thymidine hydroxylases differentially regulate the formation of glucosylated DNA at regions flanking polymerase II polycistronic transcription units throughout the genome of Trypanosoma brucei

Nucleic Acids Res. 2010 Jul;38(12):3923-35. doi: 10.1093/nar/gkq146. Epub 2010 Mar 9.


Base J is a hypermodified DNA base localized primarily to telomeric regions of the genome of Trypanosoma brucei. We have previously characterized two thymidine-hydroxylases (TH), JBP1 and JBP2, which regulate J-biosynthesis. JBP2 is a chromatin re-modeling protein that induces de novo J-synthesis, allowing JBP1, a J-DNA binding protein, to stimulate additional J-synthesis. Here, we show that both JBP2 and JBP1 are capable of stimulating de novo J-synthesis. We localized the JBP1- and JBP2-stimulated J by anti-J immunoprecipitation and high-throughput sequencing. This genome-wide analysis revealed an enrichment of base J at regions flanking polymerase II polycistronic transcription units (Pol II PTUs) throughout the T. brucei genome. Chromosome-internal J deposition is primarily mediated by JBP1, whereas JBP2-stimulated J deposition at the telomeric regions. However, the maintenance of J at JBP1-specific regions is dependent on JBP2 SWI/SNF and TH activity. That similar regions of Leishmania major also contain base J highlights the functional importance of the modified base at Pol II PTUs within members of the kinetoplastid family. The regulation of J synthesis/localization by two THs and potential biological function of J in regulating kinetoplastid gene expression is discussed.

Publication types

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

MeSH terms

  • Animals
  • Cell Line
  • DNA, Protozoan / chemistry
  • DNA, Protozoan / metabolism*
  • DNA-Binding Proteins / metabolism*
  • Genome, Protozoan
  • Glucosides / biosynthesis*
  • Histones / analysis
  • Mixed Function Oxygenases / metabolism*
  • Protozoan Proteins / metabolism*
  • RNA Polymerase II / metabolism
  • Thymidine / metabolism
  • Transcription, Genetic
  • Trypanosoma brucei brucei / enzymology
  • Trypanosoma brucei brucei / genetics*
  • Uracil / analogs & derivatives*
  • Uracil / biosynthesis


  • DNA, Protozoan
  • DNA-Binding Proteins
  • Glucosides
  • Histones
  • J-binding protein, Trypanosoma brucei
  • Protozoan Proteins
  • 5-((glucopyranosyloxy)methyl)uracil
  • Uracil
  • Mixed Function Oxygenases
  • RNA Polymerase II
  • Thymidine