Polycomb protein Cbx4 promotes SUMO modification of de novo DNA methyltransferase Dnmt3a

Bing Li, Jing Zhou, Peng Liu, Jialei Hu, Hong Jin, Yohei Shimono, Masahide Takahashi, Guoliang Xu

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63 Citations (Scopus)


The 'de novo methyltransferase' Dnmt3a (DNA methyltransferase 3a) has been shown to mediate transcriptional repression. Post-translational modification of Dnmt3a by SUMOylation affects its ability to transcriptionally repress. However, very little is known about how the SUMOylation process is regulated. In the present study, we identified a PcG (Polycomb group) protein, Cbx4 (chromobox 4), as a specific interaction partner of Dnmt3a. Co-expression of Cbx4 and SUMO-1 (small ubiquitin-related modifier-1) along with Dnmt3a in transfected cells results in enhanced modification of Dnmt3a with SUMO-1. Purified Cbx4 also promotes SUMOylation of Dnmt3a in vitro. The modification occurs in the N-terminal regulatory region, including the PWWP (Pro-Trp-Trp-Pro) domain. Our results suggest that Cbx4 functions as a SUMO E3 ligase for Dnmt3a and it might be involved in the functional regulation of DNA methyltransferases by promoting their SUMO modification.

Original languageEnglish
Pages (from-to)369-378
Number of pages10
JournalBiochemical Journal
Issue number2
Publication statusPublished - 15-07-2007
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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