Abstract
Activation-induced deaminase (AID)/APOBEC–family cytosine deaminases, known to function in diverse cellular processes from antibody diversification to mRNA editing, have also been implicated in DNA demethylation, a major process for transcriptional activation. Although oxidation-dependent pathways for demethylation have been described, pathways involving deamination of either 5-methylcytosine (5mC) or 5-hydroxymethylcytosine (5hmC) have emerged as alternatives. Here we address the biochemical plausibility of deamination-coupled demethylation. We found that purified AID/APOBECs have substantially reduced activity on 5mC relative to cytosine, their canonical substrate, and no detectable deamination of 5hmC. This finding was explained by the reactivity of a series of modified substrates, where steric bulk was increasingly detrimental to deamination. Further, upon AID/APOBEC overexpression, the deamination product of 5hmC was undetectable in genomic DNA, whereas oxidation intermediates remained detectable. Our results indicate that the steric requirements for cytosine deamination are one intrinsic barrier to the proposed function of deaminases in DNA demethylation.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
£169.00 per year
only £14.08 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Nabel, C.S., Manning, S.A. & Kohli, R.M. The curious chemical biology of cytosine: deamination, methylation, and oxidation as modulators of genomic potential. 7, 20–30 ACS Chem. Biol. (2012).
Rosenberg, B.R. & Papavasiliou, F.N. Beyond SHM and CSR: AID and related cytidine deaminases in the host response to viral infection. Adv. Immunol. 94, 215–244 (2007).
Teperek-Tkacz, M., Pasque, V., Gentsch, G. & Ferguson-Smith, A.C. Epigenetic reprogramming: is deamination key to active DNA demethylation? Reproduction 142, 621–632 (2011).
Fritz, E.L. & Papavasiliou, F.N. Cytidine deaminases: AIDing DNA demethylation? Genes Dev. 24, 2107–2114 (2010).
Bird, A. DNA methylation patterns and epigenetic memory. Genes Dev. 16, 6–21 (2002).
Tahiliani, M. et al. Conversion of 5-methylcytosine to 5-hydroxymethylcytosine in mammalian DNA by MLL partner TET1. Science 324, 930–935 (2009).
Ito, S. et al. Role of Tet proteins in 5mC to 5hmC conversion, ES-cell self-renewal and inner cell mass specification. Nature 466, 1129–1133 (2010).
Münzel, M., Globisch, D. & Carell, T. 5-Hydroxymethylcytosine, the sixth base of the genome. Angew. Chem. Int. Edn Engl. 50, 6460–6468 (2011).
Wu, H. & Zhang, Y. Mechanisms and functions of Tet protein-mediated 5-methylcytosine oxidation. Genes Dev. 25, 2436–2452 (2011).
Pastor, W.A. et al. Genome-wide mapping of 5-hydroxymethylcytosine in embryonic stem cells. Nature 473, 394–397 (2011).
Hajkova, P. Epigenetic reprogramming in the germline: towards the ground state of the epigenome. Phil. Trans. R. Soc. Lond. B 366, 2266–2273 (2011).
Wu, S.C. & Zhang, Y. Active DNA demethylation: many roads lead to Rome. Nat. Rev. Mol. Cell Biol. 11, 607–620 (2010).
Morgan, H.D., Dean, W., Coker, H.A., Reik, W. & Petersen-Mahrt, S.K. Activation-induced cytidine deaminase deaminates 5-methylcytosine in DNA and is expressed in pluripotent tissues: implications for epigenetic reprogramming. J. Biol. Chem. 279, 52353–52360 (2004).
Guo, J.U., Su, Y., Zhong, C., Ming, G.L. & Song, H. Hydroxylation of 5-methylcytosine by TET1 promotes active DNA demethylation in the adult brain. Cell 145, 423–434 (2011).
Ito, S. et al. Tet proteins can convert 5-methylcytosine to 5-formylcytosine and 5-carboxylcytosine. Science 333, 1300–1303 (2011).
He, Y.F. et al. Tet-mediated formation of 5-carboxylcytosine and its excision by TDG in mammalian DNA. Science 333, 1303–1307 (2011).
Maiti, A. & Drohat, A.C. Thymine DNA glycosylase can rapidly excise 5-formylcytosine and 5-carboxylcytosine: potential implications for active demethylation of CpG sites. J. Biol. Chem. 286, 35334–35338 (2011).
Pfaffeneder, T. et al. The discovery of 5-formylcytosine in embryonic stem cell DNA. Angew. Chem. Int. Edn Engl. 50, 7008–7012 (2011).
Zhang, L. et al. Thymine DNA glycosylase specifically recognizes 5-carboxylcytosine-modified DNA. Nat. Chem. Biol. 8, 328–330 (2012).
Cortázar, D. et al. Embryonic lethal phenotype reveals a function of TDG in maintaining epigenetic stability. Nature 470, 419–423 (2011).
Cortellino, S. et al. Thymine DNA glycosylase is essential for active DNA demethylation by linked deamination-base excision repair. Cell 146, 67–79 (2011).
Conticello, S.G., Langlois, M.A., Yang, Z. & Neuberger, M.S. DNA deamination in immunity: AID in the context of its APOBEC relatives. Adv. Immunol. 94, 37–73 (2007).
Bransteitter, R., Pham, P., Scharff, M.D. & Goodman, M.F. Activation-induced cytidine deaminase deaminates deoxycytidine on single-stranded DNA but requires the action of RNase. Proc. Natl. Acad. Sci. USA 100, 4102–4107 (2003).
Larijani, M. et al. Methylation protects cytidines from AID-mediated deamination. Mol. Immunol. 42, 599–604 (2005).
Bhutani, N. et al. Reprogramming towards pluripotency requires AID-dependent DNA demethylation. Nature 463, 1042–1047 (2010).
Popp, C. et al. Genome-wide erasure of DNA methylation in mouse primordial germ cells is affected by AID deficiency. Nature 463, 1101–1105 (2010).
Muramatsu, M. et al. Class switch recombination and hypermutation require activation-induced cytidine deaminase (AID), a potential RNA editing enzyme. Cell 102, 553–563 (2000).
Rai, K. et al. DNA demethylation in zebrafish involves the coupling of a deaminase, a glycosylase, and gadd45. Cell 135, 1201–1212 (2008).
Kohli, R.M. et al. A portable hotspot recognition loop transfers sequence preferences from APOBEC family members to activation-induced cytidine deaminase. J. Biol. Chem. 284, 22898–22904 (2009).
Larijani, M., Frieder, D., Basit, W. & Martin, A. The mutation spectrum of purified AID is similar to the mutability index in Ramos cells and in ung(−/−) msh2(−/−) mice. Immunogenetics 56, 840–845 (2005).
Beale, R.C. et al. Comparison of the differential context-dependence of DNA deamination by APOBEC enzymes: correlation with mutation spectra in vivo. J. Mol. Biol. 337, 585–596 (2004).
Prochnow, C., Bransteitter, R., Klein, M.G., Goodman, M.F. & Chen, X.S. The APOBEC-2 crystal structure and functional implications for the deaminase AID. Nature 445, 447–451 (2007).
Hansch, C. et al. “Aromatic” substituent constants for structure-activity correlations. J. Med. Chem. 16, 1207–1216 (1973).
Pearl, L.H. Structure and function in the uracil-DNA glycosylase superfamily. Mutat. Res. 460, 165–181 (2000).
Bennett, M.T. et al. Specificity of human thymine DNA glycosylase depends on N-glycosidic bond stability. J. Am. Chem. Soc. 128, 12510–12519 (2006).
Kavli, B. et al. Excision of cytosine and thymine from DNA by mutants of human uracil-DNA glycosylase. EMBO J. 15, 3442–3447 (1996).
Guo, J.U., Su, Y., Zhong, C., Ming, G.L. & Song, H. Emerging roles of TET proteins and 5-hydroxymethylcytosines in active DNA demethylation and beyond. Cell Cycle 10, 2662–2668 (2011).
Globisch, D. et al. Tissue distribution of 5-hydroxymethylcytosine and search for active demethylation intermediates. PLoS ONE 5, e15367 (2010).
Kohli, R.M. et al. Local sequence targeting in the AID/APOBEC family differentially impacts retroviral restriction and antibody diversification. J. Biol. Chem. 285, 40956–40964 (2010).
Pham, P., Bransteitter, R., Petruska, J. & Goodman, M.F. Processive AID-catalysed cytosine deamination on single-stranded DNA simulates somatic hypermutation. Nature 424, 103–107 (2003).
Bruniquel, D. & Schwartz, R.H. Selective, stable demethylation of the interleukin-2 gene enhances transcription by an active process. Nat. Immunol. 4, 235–240 (2003).
Martinowich, K. et al. DNA methylation-related chromatin remodeling in activity-dependent BDNF gene regulation. Science 302, 890–893 (2003).
Liu, M. et al. Two levels of protection for the B cell genome during somatic hypermutation. Nature 451, 841–845 (2008).
Landry, S., Narvaiza, I., Linfesty, D.C. & Weitzman, M.D. APOBEC3A can activate the DNA damage response and cause cell-cycle arrest. EMBO Rep. 12, 444–450 (2011).
Grogan, B.C., Parker, J.B., Guminski, A.F. & Stivers, J.T. Effect of the thymidylate synthase inhibitors on dUTP and TTP pool levels and the activities of DNA repair glycosylases on uracil and 5-fluorouracil in DNA. Biochemistry 50, 618–627 (2011).
Acknowledgements
We are grateful to M. Bartolomei, M. Weitzman and M. Lazar for helpful discussions, K. Gajula and S. Manning for technical assistance and the University of North Carolina Biomarker Mass Spectrometry Facility for guidance. We are also grateful for A. Drohat (University of Maryland), A. Guminski (Johns Hopkins University) and J. Guo and H. Song (Johns Hopkins University) for providing reagents. This work was supported in part by the Rita Allen Foundation (to R.M.K.), the W. W. Smith Charitable Trust (to R.M.K.) and US National Institutes of Health grants K08-AI089242 (to R.M.K.), GM056834 (to J.T.S.) and U01DK089565 (to Y.Z.). Y.Z. is an investigator of the Howard Hughes Medical Institute.
Author information
Authors and Affiliations
Contributions
R.M.K., J.T.S. and Y.Z. conceived the project. R.M.K., J.T.S., Y.Y., C.S.N. and Y.Z. designed the experiments. C.S.N., H.J., Y.Y., L.S. and H.L.G. performed the experiments. C.S.N., H.J. and L.S. analyzed the data. C.S.N., H.J., L.S., H.L.G., J.T.S., Y.Z. and R.M.K. interpreted the data. C.S.N., J.T.S. and R.M.K. wrote the manuscript, and all authors edited the manuscript.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Text and Figures
Supplementary Methods and Supplementary Results (PDF 1000 kb)
Rights and permissions
About this article
Cite this article
Nabel, C., Jia, H., Ye, Y. et al. AID/APOBEC deaminases disfavor modified cytosines implicated in DNA demethylation. Nat Chem Biol 8, 751–758 (2012). https://doi.org/10.1038/nchembio.1042
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nchembio.1042