5-Formylcytosine landscapes of human preimplantation embryos at single-cell resolution

PLoS Biol. 2020 Jul 30;18(7):e3000799. doi: 10.1371/journal.pbio.3000799. eCollection 2020 Jul.

Abstract

Epigenetic dynamics, such as DNA methylation and chromatin accessibility, have been extensively explored in human preimplantation embryos. However, the active demethylation process during this crucial period remains largely unexplored. In this study, we use single-cell chemical-labeling-enabled C-to-T conversion sequencing (CLEVER-seq) to quantify the DNA 5-formylcytosine (5fC) levels of human preimplantation embryos. We find that 5-formylcytosine phosphate guanine (5fCpG) exhibits genomic element-specific distribution features and is enriched in L1 and endogenous retrovirus-K (ERVK), the subfamilies of repeat elements long interspersed nuclear elements (LINEs) and long terminal repeats (LTRs), respectively. Unlike in mice, paired pronuclei in the same zygote present variable difference of 5fCpG levels, although the male pronuclei experience stronger global demethylation. The nucleosome-occupied regions show a higher 5fCpG level compared with nucleosome-depleted ones, suggesting the role of 5fC in organizing nucleosome position. Collectively, our work offers a valuable resource for ten-eleven translocation protein family (TET)-dependent active demethylation-related study during human early embryonic development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blastocyst / metabolism*
  • Cytosine / analogs & derivatives*
  • Cytosine / metabolism
  • DNA Demethylation*
  • Embryonic Development
  • Genome, Human
  • Humans
  • Regulatory Elements, Transcriptional
  • Single-Cell Analysis

Substances

  • 5-formylcytosine
  • Cytosine

Grants and funding

This project was supported by Beijing Municipal Science & Technology Commission (Z181100001318001 to F.T.). This project was also supported by grants from National Key R&D Program of China (2018YFC1003100 to L.W., 2018YFA0107601 and 2017YFA0102702 to F.T.). This project was also supported by grants from the National Natural Science Foundation of China (81521002 to J.Q. and F.T., 81730038 and 31871482 to J.Q., 31571544 and 31871447 to L.Y., 31625018 to F.T.). The work was also supported by the Beijing Advanced Innovation Center for Genomics at Peking University (F.T. and J.Q.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.