title: Loss of Pcgf5 Affects Global H2A Monoubiquitination but Not the Function of Hematopoietic Stem and Progenitor Cells.
abstract: Polycomb-group RING finger proteins (Pcgf1-Pcgf6) are components of Polycomb repressive complex 1 (PRC1)-related complexes that catalyze monoubiquitination of histone H2A at lysine 119 (H2AK119ub1), an epigenetic mark associated with repression of genes. Pcgf5 has been characterized as a component of PRC1.5, one of the non-canonical PRC1, consisting of Ring1a/b, Rybp/Yaf2 and Auts2. However, the biological functions of Pcgf5 have not yet been identified. Here we analyzed the impact of the deletion of Pcgf5 specifically in hematopoietic stem and progenitor cells (HSPCs). Pcgf5 is expressed preferentially in hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs) compared with committed myeloid progenitors and differentiated cells. We transplanted bone marrow (BM) cells from Rosa::Cre-ERT control and Cre-ERT;Pcgf5fl/fl mice into lethally irradiated recipient mice. At 4 weeks post-transplantation, we deleted Pcgf5 by injecting tamoxifen, however, no obvious changes in hematopoiesis were detected including the number of HSPCs during a long-term observation period following the deletion. Competitive BM repopulating assays revealed normal repopulating capacity of Pcgf5-deficient HSCs. Nevertheless, Pcgf5-deficient HSPCs showed a significant reduction in H2AK119ub1 levels compared with the control. ChIP-sequence analysis confirmed the reduction in H2AK119ub1 levels, but revealed no significant association of changes in H2AK119ub1 levels with gene expression levels. Our findings demonstrate that Pcgf5-containing PRC1 functions as a histone modifier in vivo, but its role in HSPCs is limited and can be compensated by other PRC1-related complexes in HSPCs.
authors.affiliation: Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Sha
authors.initials: S
authors.lastname: Si
authors.affiliation: Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Yaeko
authors.initials: Y
authors.lastname: Nakajima-Takagi
authors.affiliation: Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Aoyama
authors.affiliation: Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Motohiko
authors.initials: M
authors.lastname: Oshima
authors.affiliation: Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Atsunori
authors.initials: A
authors.lastname: Saraya
authors.affiliation: Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sugishita
authors.affiliation: Chromosome Engineering Team, Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakayama
authors.affiliation: Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ishikura
authors.affiliation: Laboratory for Developmental Genetics, RIKEN Center for Integrative Medical Sciences (IMS), Yokohama, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Koseki
authors.affiliation: Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iwama
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D047369:Chromatin Immunoprecipitation; D005838:Genotype; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D063150:Polycomb Repressive Complex 1 / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D054875:Ubiquitination / Q000235:genetics / Q000502:physiology
chemical_list: D006657:Histones; C570527:Pcgf1 protein, mouse; D063150:Polycomb Repressive Complex 1