title: A protein interaction network for pluripotency of embryonic stem cells.
abstract: Embryonic stem (ES) cells are pluripotent and of therapeutic potential in regenerative medicine. Understanding pluripotency at the molecular level should illuminate fundamental properties of stem cells and the process of cellular reprogramming. Through cell fusion the embryonic cell phenotype can be imposed on somatic cells, a process promoted by the homeodomain protein Nanog, which is central to the maintenance of ES cell pluripotency. Nanog is thought to function in concert with other factors such as Oct4 (ref. 8) and Sox2 (ref. 9) to establish ES cell identity. Here we explore the protein network in which Nanog operates in mouse ES cells. Using affinity purification of Nanog under native conditions followed by mass spectrometry, we have identified physically associated proteins. In an iterative fashion we also identified partners of several Nanog-associated proteins (including Oct4), validated the functional relevance of selected newly identified components and constructed a protein interaction network. The network is highly enriched for nuclear factors that are individually critical for maintenance of the ES cell state and co-regulated on differentiation. The network is linked to multiple co-repressor pathways and is composed of numerous proteins whose encoding genes are putative direct transcriptional targets of its members. This tight protein network seems to function as a cellular module dedicated to pluripotency.
authors.affiliation: Division of Hematology-Oncology, Children's Hospital and Dana Farber Cancer Institute, Harvard Medical School, Harvard Stem Cell Institute, Boston, Massachusetts 02115, USA.
authors.forename: Jianlong
authors.initials: J
authors.lastname: Wang
authors.forename: Sridhar
authors.initials: S
authors.lastname: Rao
authors.forename: Jianlin
authors.initials: J
authors.lastname: Chu
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Shen
authors.forename: Dana N
authors.initials: DN
authors.lastname: Levasseur
authors.forename: Thorold W
authors.initials: TW
authors.lastname: Theunissen
authors.forename: Stuart H
authors.initials: SH
authors.lastname: Orkin
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D000071317:Nanog Homeobox Protein; D039904:Pluripotent Stem Cells / Q000378:metabolism*; D011485:Protein Binding; D034622:RNA Interference; D015203:Reproducibility of Results
chemical_list: D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D046912:Multiprotein Complexes; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse