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Hypoxia sensing by Fe2+/α‐KG dependent dioxygenases regulate hmU synthesis in trypanosome DNA, chromatin structure and Pol II transcription
Author(s) -
sabatini robert,
cliffe laura,
ekanayake dilrukshi,
Hirsch Gwen
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.535.16
Subject(s) - biology , transcription (linguistics) , dna , chromatin , histone , gene , microbiology and biotechnology , biochemistry , philosophy , linguistics
We have recently demonstrated that O‐linked glucosylation of thymine (base J) in trypanosome DNA regulates Pol II transcription initiation in organisms previously thought to lack transcriptional regulation. Trypanosome cruzi cell lines with reduced levels of base J following the deletion of the thymidine hydroxylase (JBP1) involved in J synthesis resulted in genome‐wide changes in gene expression and increased parasite virulence. Addressing the mechanism of base J function, we now find that the loss of base J coincides with decreased nucleosome abundance, increased histone acetylation and increased Pol II occupancy at promoter regions. In vivo analysis suggest the thymidine hydroxylases (JBP1 and JBP2) belong to the Fe2+/α‐KG dependent dioxygenase superfamily where hydroxylation is driven by the oxidative decarboxylation of αKG, forming succinate and CO2. We now demonstrate that recombinant JBP1 can hydroxylate synthetic DNA substrates in a Fe2+, α‐KG and oxygen dependent manner. Growth of T. cruzi in hypoxic conditions (<1% oxygen) results in a significant reduction in J levels, which is rapidly restored upon re‐exposure to oxygen, and increased parasite virulence as seen in the JBP KO's. The influence of environment upon J biosynthesis, via JBP, has exciting implications for the regulation of gene expression and parasite survival and adaptation to different host environments. Supported by NIH.