Search

Objectives: The level of histone H3 lysine 79 methylation is regulated by the cell cycle and involved in cell proliferation. KDM2B is an H3K79 demethylase. Proliferating cell nuclear antigen (PCNA) is a component of the DNA replication machinery. This study aimed at elucidating a molecular link between H3K79me recognition of PCNA and cell cycle control., Materials and Methods: We generated KDM2B-depleted 293T cells and histone H3-K79R mutant-expressing 293T cells. Western blots were primarily utilized to examine the H3K79me level and its effect on subsequent PCNA dissociation from chromatin. We applied IP, peptide pull-down, isothermal titration calorimetry (ITC) and ChIP experiments to show the PCNA binding towards methylated H3K79 and DNA replication origins. Flow cytometry, MTT, iPOND and DNA fibre assays were used to assess the necessity of KDM2B for DNA replication and cell proliferation., Results: We revealed that KDM2B-mediated H3K79 demethylation regulated cell cycle progression. We found that PCNA bound chromatin in an H3K79me-dependent manner during S phase. KDM2B was responsible for the timely dissociation of PCNA from chromatin, allowing to efficient DNA replication. Depletion of KDM2B aberrantly enriched chromatin with PCNA and caused slow dissociation of residual PCNA, leading to a negative effect on cell proliferation., Conclusions: We suggested a novel interaction between PCNA and H3K79me. Thus, our findings provide a new mechanism of KDM2B in regulation of DNA replication and cell proliferation., (© 2020 The Authors. Cell Proliferation Published by John Wiley & Sons Ltd.)

Epigenetic dysregulation has been strongly implicated in carcinogenesis and is one of the mechanisms that contribute to the development of lung cancer. Using genome-wide CRISPR/Cas9 library screening, we showed SET domain-containing protein 1A (SETD1A) is an essential epigenetic modifier of the proliferation of NSCLC H1299 cells. Depletion of SETD1A strikingly inhibited the proliferation of NSCLC cells. IHC staining and bioinformatics showed that SETD1A is upregulated in lung cancer. Kaplan-Meier survival analysis indicated that high expression of SETD1A is associated with poor prognosis of patients with NSCLC. We revealed that loss of SETD1A inhibits DNA replication and induces replication stress accompanied by impaired fork progression. In addition, transcription of CDC7 and TOP1, which are involved in replication origin activation and fork progression, respectively, was significantly reduced by knockdown of SETD1A. Taken together, these findings demonstrated SETD1A is a critical epigenetic modifier of NSCLC cell proliferation by promoting the transcription of a subset of DNA replication-associated genes. • SETD1A is an essential epigenetic modifier for proliferation of H1299 cells. • SETD1A knockdown impairs replication fork progression and induces replication stress. • SETD1A is required to transcription of S-phase associated target gene s via H3K4me3 methylation. [ABSTRACT FROM AUTHOR]