TY - JOUR
T1 - Ascorbate-induced generation of 5-hydroxymethylcytosine is unaffected by varying levels of iron and 2-oxoglutarate
AU - Dickson, Kevin M.
AU - Gustafson, Christopher B.
AU - Young, Juan I.
AU - Züchner, Stephan
AU - Wang, Gaofeng
N1 - Funding Information:
We thank Brenda Court for technical support. This research was supported by a James and Esther King biomedical research award ( 3KN08 ) to G.W. and a NIH grant ( R01NS075764 ) to S.Z.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 2013/10/4
Y1 - 2013/10/4
N2 - Tet (ten-eleven translocation) methylcytosine dioxygenases, which belong to the iron and 2-oxoglutarate (2OG)-dependent dioxygenase superfamily, convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. We recently reported that ascorbate (vitamin C) induces Tet-mediated generation of 5hmC. To initially delineate the role of ascorbate on 5hmC generation, we analyzed whether the effect of ascorbate is dependent upon the conditions of other components involved in the hydroxylation of 5mC catalyzed by Tet. We found that removing iron from the culture medium did not affect the induction of 5hmC by ascorbate (10. μM) in mouse embryonic fibroblasts (MEFs). The effect of ascorbate did not involve an increased expression of Tet1-3 or isocitrate dehydrogenases (IDH1-2), the enzymes responsible for producing 2OG. Interestingly, MEFs cultured with different concentrations of glucose, a major precursor of 2OG, exhibited nearly identical responses to ascorbate treatment. Further, blocking the uptake of the reduced form of vitamin C, ascorbic acid, through the sodium-dependent vitamin C transporters (SVCTs) inhibited the effect of ascorbate on 5hmC. However, inhibition of the facilitative glucose transporters (GLUTs), which mediate the incorporation of the oxidized form of vitamin C, dehydroascorbic acid (DHA), did not modify the ability of ascorbate to induce 5hmC generation. These results indicate that the effect of ascorbate on 5hmC is not dependent upon iron uptake, the expression of Tet and IDH, or the production of 2OG, suggesting that ascorbate may directly participate in the generation of 5hmC, most likely as a cofactor of Tet.
AB - Tet (ten-eleven translocation) methylcytosine dioxygenases, which belong to the iron and 2-oxoglutarate (2OG)-dependent dioxygenase superfamily, convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. We recently reported that ascorbate (vitamin C) induces Tet-mediated generation of 5hmC. To initially delineate the role of ascorbate on 5hmC generation, we analyzed whether the effect of ascorbate is dependent upon the conditions of other components involved in the hydroxylation of 5mC catalyzed by Tet. We found that removing iron from the culture medium did not affect the induction of 5hmC by ascorbate (10. μM) in mouse embryonic fibroblasts (MEFs). The effect of ascorbate did not involve an increased expression of Tet1-3 or isocitrate dehydrogenases (IDH1-2), the enzymes responsible for producing 2OG. Interestingly, MEFs cultured with different concentrations of glucose, a major precursor of 2OG, exhibited nearly identical responses to ascorbate treatment. Further, blocking the uptake of the reduced form of vitamin C, ascorbic acid, through the sodium-dependent vitamin C transporters (SVCTs) inhibited the effect of ascorbate on 5hmC. However, inhibition of the facilitative glucose transporters (GLUTs), which mediate the incorporation of the oxidized form of vitamin C, dehydroascorbic acid (DHA), did not modify the ability of ascorbate to induce 5hmC generation. These results indicate that the effect of ascorbate on 5hmC is not dependent upon iron uptake, the expression of Tet and IDH, or the production of 2OG, suggesting that ascorbate may directly participate in the generation of 5hmC, most likely as a cofactor of Tet.
KW - 2-Oxoglutarate
KW - 5-Hydroxymethylcytosine
KW - Ascorbate
KW - Glucose
KW - Iron
KW - Isocitrate dehydrogenase
KW - Sodium-dependent vitamin C transporter
KW - Tet methylcytosine dioxygenase
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U2 - 10.1016/j.bbrc.2013.09.010
DO - 10.1016/j.bbrc.2013.09.010
M3 - Article
C2 - 24021282
AN - SCOPUS:84884704614
VL - 439
SP - 522
EP - 527
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 4
ER -