title: Rb and p107 regulate preadipocyte differentiation into white versus brown fat through repression of PGC-1alpha.
abstract: The Rb family, Rb, p107, and p130, play important roles in cell cycle control and cellular differentiation, and Rb has been suggested to regulate adipocyte differentiation. We report here that mice lacking p107 displayed a uniform replacement of white adipose tissue (WAT) with brown adipose tissue (BAT). Mutant WAT depots contained mutilocular adipocytes that expressed elevated levels of PGC-1alpha and UCP-1 typical of BAT. WAT from p107-/- mice contained markedly elevated numbers of adipogenic precursors that displayed downregulated expression of pRb. Consistent with the hypothesis that pRb is required for adult adipocyte differentiation, Cre-mediated deletion of Rb in adult primary preadipocytes blocked their differentiation into white adipocytes. Importantly, pRb was observed to bind the PGC-1alpha promoter and repress transcription. Therefore, p107 and pRb regulate PGC-1alpha expression to control the switch between white and brown adipocyte differentiation from a common pool of presumptive adult progenitors in fat tissue.
authors.affiliation: Molecular Medicine Program, Ottawa Health Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Scimè
authors.forename: Guillaume
authors.initials: G
authors.lastname: Grenier
authors.forename: Michael S
authors.initials: MS
authors.lastname: Huh
authors.forename: Mark A
authors.initials: MA
authors.lastname: Gillespie
authors.forename: Lisa
authors.initials: L
authors.lastname: Bevilacqua
authors.forename: Mary-Ellen
authors.initials: ME
authors.lastname: Harper
authors.forename: Michael A
authors.initials: MA
authors.lastname: Rudnicki
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000502:physiology*; D002001:Adipose Tissue, Brown / Q000166:cytology* / Q000378:metabolism; D052436:Adipose Tissue, White / Q000166:cytology* / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D011401:Promoter Regions, Genetic; D012313:RNA / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D050720:Retinoblastoma-Like Protein p107 / Q000235:genetics* / Q000378:metabolism; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014284:Triiodothyronine / Q000494:pharmacology; D000071256:Uncoupling Protein 1
chemical_list: D007473:Ion Channels; D024101:Mitochondrial Proteins; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; C489485:Rbl1 protein, mouse; D016160:Retinoblastoma Protein; D050720:Retinoblastoma-Like Protein p107; D045162:Thiazolidinediones; D015534:Trans-Activators; D014157:Transcription Factors; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; D000077154:Rosiglitazone; D014284:Triiodothyronine; D012313:RNA