The zinc finger CCCTC-binding protein (CTCF) carries out many functions in the cell. Although previous studies sought to explain CTCF multivalency based on sequence composition of binding sites, few examined how CTCF post-translational modification (PTM) could contribute to function. Here, we performed CTCF mass spectrometry, identified a novel phosphorylation site at Serine 224 (Ser224-P), and demonstrate that phosphorylation is carried out by Polo kinase 1 (PLK1). CTCF Ser224-P is chromatin-associated, mapping to at least a subset of known CTCF sites. CTCF Ser224-P accumulates during the G2/M transition of the cell cycle and is enriched at pericentric regions. The phospho-obviation mutant, S224A, appeared normal. However, the phospho-mimic mutant, S224E, is detrimental to mouse embryonic stem cell colonies. While ploidy and chromatin architecture appear unaffected, S224E mutants differentially express of hundreds of genes, including p53 and p21. We have thus identified a new CTCF PTM and provided evidence of biological function.
High-throughput sequencing data are available in the National Center for Biotechnology Information GEO repository under accession GSE119697
High-throughput sequencing dataNCBI Gene Expression Omnibus, GSE119697.
- Jeannie T Lee
- Jeannie T Lee
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Jessica K Tyler, Weill Cornell Medicine, United States
© 2019, del Rosario et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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A new in vitro system called Rec-Seq sheds light on how mRNA molecules compete for the machinery that translates their genetic sequence into proteins.