title: RBPJ, the major transcriptional effector of Notch signaling, remains associated with chromatin throughout mitosis, suggesting a role in mitotic bookmarking.
abstract: Mechanisms that maintain transcriptional memory through cell division are important to maintain cell identity, and sequence-specific transcription factors that remain associated with mitotic chromatin are emerging as key players in transcriptional memory propagation. Here, we show that the major transcriptional effector of Notch signaling, RBPJ, is retained on mitotic chromatin, and that this mitotic chromatin association is mediated through the direct association of RBPJ with DNA. We further demonstrate that RBPJ binds directly to nucleosomal DNA in vitro, with a preference for sites close to the entry/exit position of the nucleosomal DNA. Genome-wide analysis in the murine embryonal-carcinoma cell line F9 revealed that roughly 60% of the sites occupied by RBPJ in asynchronous cells were also occupied in mitotic cells. Among them, we found that a fraction of RBPJ occupancy sites shifted between interphase and mitosis, suggesting that RBPJ can be retained on mitotic chromatin by sliding on DNA rather than disengaging from chromatin during mitotic chromatin condensation. We propose that RBPJ can function as a mitotic bookmark, marking genes for efficient transcriptional activation or repression upon mitotic exit. Strikingly, we found that sites of RBPJ occupancy were enriched for CTCF-binding motifs in addition to RBPJ-binding motifs, and that RBPJ and CTCF interact. Given that CTCF regulates transcription and bridges long-range chromatin interactions, our results raise the intriguing hypothesis that by collaborating with CTCF, RBPJ may participate in establishing chromatin domains and/or long-range chromatin interactions that could be propagated through cell division to maintain gene expression programs.
authors.affiliation: Epigenetics Program, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Lake
authors.affiliation: Epigenetics Program, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Pei-Fang
authors.initials: PF
authors.lastname: Tsai
authors.affiliation: Institute for Diabetes Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Inchan
authors.initials: I
authors.lastname: Choi
authors.affiliation: Institute for Diabetes Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Kyoung-Jae
authors.initials: KJ
authors.lastname: Won
authors.affiliation: Epigenetics Program, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America; Institute for Diabetes Obesity and Metabolism, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Hua-Ying
authors.initials: HY
authors.lastname: Fan
mesh_terms: D000818:Animals; D000076246:CCCTC-Binding Factor; D002843:Chromatin / Q000235:genetics*; D004247:DNA / Q000235:genetics*; D006801:Humans; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000235:genetics* / Q000378:metabolism; D007399:Interphase / Q000235:genetics; D051379:Mice; D008938:Mitosis / Q000235:genetics*; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics
chemical_list: D000076246:CCCTC-Binding Factor; C000619697:CTCF protein, human; D002843:Chromatin; C000619698:Ctcf protein, mouse; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D009707:Nucleosomes; C497571:Rbpj protein, mouse; D051880:Receptors, Notch; D012097:Repressor Proteins; D014157:Transcription Factors; D004247:DNA