title: Forced expression of the histone demethylase Fbxl10 maintains self-renewing hematopoietic stem cells.
abstract: OBJECTIVE
  The methylation status of histones changes dramatically depending on cellular context and defines cell type-specific gene expression profiles. Histone demethylases have recently been implicated in this process. However, it is unknown how histone demethylases function in the maintenance of self-renewing hematopoietic stem cells (HSCs).
  
  
  METHODS
  We profiled the expression of histone demethylase genes in mouse hematopoietic cells and listed genes preferentially expressed in HSCs. We analyzed the impact of a selected gene by transducing CD34(-)c-Kit(+)Sca-1(+)lineage marker(-) (CD34(-)KSL) HSCs using retroviral system followed by in vitro methylcellulose colony assays and in vivo competitive repopulation assays.
  
  
  RESULTS
  We found that F-box and leucine-rich repeat protein 10 (Fbxl10, also known as Jhdm1b or Kdm2b), is highly expressed in CD34(-)KSL HSCs. Fbxl10 encodes a demethylase specific to the histone H3 mono/di-methylated at lysine 36 (H3K36me1/me2) and forms complexes with polycomb-group proteins, essential regulators of HSCs. Forced expression of Fbxl10 in HSCs expanded numbers of colony-forming cells with multilineage differentiation potential in culture and prevented exhaustion of the long-term repopulating potential of HSCs following serial transplantation. Fbxl10 tightly repressed the expression of cyclin-dependent kinase inhibitor genes, including Ink4a, Ink4b, and Ink4c, through direct binding to their promoters and gene bodies and demethylation at H3K36. Increased levels of mono-ubiquitylation of H2A at target loci also suggested the collaboration of Fbxl10 with polycomb-group proteins.
  
  
  CONCLUSIONS
  Our findings implicate Fbxl10 in the maintenance of self-renewal capacity of HSCs, thus highlight a role of histone demethylation for the first time in the epigenetic regulation of HSCs.
authors.affiliation: Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan; JST, CREST, Tokyo, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Konuma
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Nakamura
authors.forename: Satoru
authors.initials: S
authors.lastname: Miyagi
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Negishi
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Chiba
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Oguro
authors.forename: Jin
authors.initials: J
authors.lastname: Yuan
authors.forename: Makiko
authors.initials: M
authors.lastname: Mochizuki-Kashio
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ichikawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miyoshi
authors.forename: Miguel
authors.initials: M
authors.lastname: Vidal
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iwama
mesh_terms: D000818:Animals; D047369:Chromatin Immunoprecipitation; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D044783:F-Box Proteins / Q000235:genetics / Q000502:physiology*; D020869:Gene Expression Profiling; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D056484:Jumonji Domain-Containing Histone Demethylases / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D044783:F-Box Proteins; D056484:Jumonji Domain-Containing Histone Demethylases; C524747:Kdm2b protein, mouse; D018844:Cyclin-Dependent Kinases