PT  - JOURNAL ARTICLE
AU  - Federica Battistini
AU  - Pablo D. Dans
AU  - Montserrat Terrazas
AU  - Chiara L. Castellazzi
AU  - Guillem Portella
AU  - Mireia Labrador
AU  - Núria Villegas
AU  - Isabelle Brun-Heath
AU  - Carlos González
AU  - Modesto Orozco
TI  - The Impact of The Hydroxymethyl-Cytosine Epigenetic Signature on DNA Structure And Function
AID  - 10.1101/2020.09.17.285452
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.09.17.285452
4099  - http://biorxiv.org/content/early/2020/09/17/2020.09.17.285452.short
4100  - http://biorxiv.org/content/early/2020/09/17/2020.09.17.285452.full
AB  - We present a comprehensive, experimental and theoretical study of the impact of 5-hydroxymethylation of DNA cytosine. Using molecular dynamics, biophysical experiments and NMR spectroscopy, we found that Ten-Eleven translocation (TET) dioxygenases generate an epigenetic variant with structural and physical properties not too different to those of 5-methylcytosine. Experiments and simulations demonstrate that 5-methyl-cytosine (mC) and 5-hydroxymethyl-cytosine (hmC) generally lead to more rigid duplexes with poorer circularization efficiencies and lower ability to form nucleosomes. In particular, we can rule out the hypothesis that hydroxymethylation reverts to unmodified cytosine physical properties, as hmC is even more rigid than mC. Thus, we do not expect dramatic changes in the chromatin structure induced by differences in physical properties between d(mCpG) and d(hmCpG). On the contrary, our simulations suggest that methylated-DNA binding domains (MBD), associated with repression activities, are very sensitive to the substitution d(mCpG)→ d(hmCpG), while MBD3 which has a dual activation/repression activity is not sensitive to the d(mCpG) → d(hmCpG) change. Overall, while changes in gene activity due to cytosine methylation are the result of the combination of stiffness-related chromatin reorganization and MBD binding, those associated to 5-hydroxylation of methylcytosine could be explained by a change in the balance of repression/activation pathways related to differential MBD binding.Competing Interest StatementThe authors have declared no competing interest.