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). MATERIALS AND 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.
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). MATERIALS AND 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: Chunxiao Xu; Christine M Fillmore; Shohei Koyama; Hongbo Wu; Yanqiu Zhao; Zhao Chen; Grit S Herter-Sprie; Esra A Akbay; Jeremy H Tchaicha; Abigail Altabef; Jacob B Reibel; Zandra Walton; Hongbin Ji; Hideo Watanabe; Pasi A Jänne; Diego H Castrillon; Anil K Rustgi; Adam J Bass; Gordon J Freeman; Robert F Padera; Glenn Dranoff; Peter S Hammerman; Carla F Kim; Kwok-Kin Wong Journal: Cancer Cell Date: 2014-05-01 Impact factor: 31.743
Authors: Sam X Li; Bradley S Barrett; Michael S Harper; Karl J Heilman; Kalani Halemano; Amanda K Steele; Kejun Guo; Robert H Silverman; Mario L Santiago Journal: Virology Date: 2013-05-29 Impact factor: 3.616