5-Formylcytosine mediated DNA–protein cross-links block DNA replication and induce mutations in human cells. Issue 13 (14th June 2018)

• Record Type: Journal Article
• Authors: Ji, Shaofei; Fu, Iwen; Naldiga, Spandana; Shao, Hongzhao; Basu, Ashis K; Broyde, Suse; Tretyakova, Natalia Y
• Is Part Of: Nucleic acids research. Volume 46:Issue 13(2018)
• Page Start: 6455
• Page End: 6469
• Publication Date: 2018-06-14
• Subjects: Nucleic acids -- Periodicals; Molecular biology -- Periodicals; 572.805
• DOI: 10.1093/nar/gky444
• Languages: English
• ISSNs: 0305-1048

Abstract

Abstract: 5-Formylcytosine (5fC) is an epigenetic DNA modification introduced via TET protein-mediated oxidation of 5-methyl-dC. We recently reported that 5fC form reversible DNA–protein conjugates (DPCs) with histone proteins in living cells (Ji et al. (2017) Angew. Chem. Int. Ed ., 56:14130–14134). We now examined the effects of 5fC mediated DPCs on DNA replication. Synthetic DNA duplexes containing site-specific DPCs between 5fC and lysine-containing proteins and peptides were subjected to primer extension experiments in the presence of human translesion synthesis DNA polymerases η and κ. We found that DPCs containing histones H2A or H4 completely inhibited DNA replication, but the replication block was removed when the proteins were subjected to proteolytic digestion. Cross-links to 11-mer or 31-mer peptides were bypassed by both polymerases in an error-prone manner, inducing targeted C→T transitions and –1 deletions. Similar types of mutations were observed when plasmids containing 5fC-peptide cross-links were replicated in human embryonic kidney (HEK) 293T cells. Molecular simulations of the 11-mer peptide-dC cross-links bound to human polymerases η and κ revealed that the peptide fits well on the DNA major groove side, and the modified dC forms a stable mismatch with incoming dATP via wobble base pairing in the polymerase active site.