Loss of the mammalian DREAM complex deregulates chondrocyte proliferation.
Mammalian DREAM is a conserved protein complex that functions in cellular quiescence. DREAM contains an E2F, a retinoblastoma (RB)-family protein, and the MuvB core (LIN9, LIN37, LIN52, LIN54, and RBBP4). In mammals, MuvB can alternatively bind to BMYB to form a complex that promotes mitotic gene expression. Because BMYB-MuvB is essential for proliferation, loss-of-function approaches to study MuvB have generated limited insight into DREAM function. Here, we report a gene-targeted mouse model that is uniquely deficient for DREAM complex assembly. We have targeted p107 (Rbl1) to prevent MuvB binding and combined it with deficiency for p130 (Rbl2). Our data demonstrate that cells from these mice preferentially assemble BMYB-MuvB complexes and fail to repress transcription. DREAM-deficient mice show defects in endochondral bone formation and die shortly after birth. Micro-computed tomography and histology demonstrate that in the absence of DREAM, chondrocytes fail to arrest proliferation. Since DREAM requires DYRK1A (dual-specificity tyrosine phosphorylation-regulated protein kinase 1A) phosphorylation of LIN52 for assembly, we utilized an embryonic bone culture system and pharmacologic inhibition of (DYRK) kinase to demonstrate a similar defect in endochondral bone growth. This reveals that assembly of mammalian DREAM is required to induce cell cycle exit in chondrocytes.
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada.
Chantal
C
Forristal
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada.
Shauna A
SA
Henley
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada.
James I
JI
MacDonald
Children's Health Research Institute, Western University, London, Ontario, Canada Department of Physiology and Pharmacology, Western University, London, Ontario, Canada.
Jason R
JR
Bush
Department of Physiology and Pharmacology, Western University, London, Ontario, Canada.
Carley
C
Ort
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada.
Daniel T
DT
Passos
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada.
Srikanth
S
Talluri
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada.
Charles A
CA
Ishak
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada.
Michael J
MJ
Thwaites
Department of Medical Biophysics, Western University, London, Ontario, Canada.
Chris J
CJ
Norley
Department of Internal Medicine, Virginia Commonwealth University, Richmond, Virginia, USA.
Larisa
L
Litovchick
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
James A
JA
DeCaprio
London Regional Cancer Program, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada Department of Oncology, Western University, London, Ontario, Canada.
Gabriel
G
DiMattia
Department of Medical Biophysics, Western University, London, Ontario, Canada.
David W
DW
Holdsworth
Children's Health Research Institute, Western University, London, Ontario, Canada Department of Physiology and Pharmacology, Western University, London, Ontario, Canada.
Frank
F
Beier
London Regional Cancer Program, Western University, London, Ontario, Canada Children's Health Research Institute, Western University, London, Ontario, Canada Department of Biochemistry, Western University, London, Ontario, Canada Department of Oncology, Western University, London, Ontario, Canada fdick@uwo.ca.
Frederick A
FA
Dick
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D002453:Cell Cycle / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000378:metabolism / Q000473:pathology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006247:Harmine / Q000494:pharmacology; D006801:Humans; D008322:Mammals / Q000378:metabolism*; D051379:Mice; D008817:Mice, Mutant Strains; D023421:Models, Animal; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010012:Osteogenesis / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D016160:Retinoblastoma Protein / Q000378:metabolism; D013977:Tibia / Q000187:drug effects / Q000378:metabolism / Q000473:pathology
D046912:Multiprotein Complexes; D016160:Retinoblastoma Protein; D006247:Harmine