title: Morpholino-mediated knockdown in primary chondrocytes implicates Hoxc8 in regulation of cell cycle progression.
abstract: Numerous experiments in mutant and transgenic mice have implicated Hox transcription factors in development of the skeletal system, postulating a role for these proteins in cell proliferation of precursor cells and regulation of cell differentiation. Our own data from Hoxc8 and Hoxd4 transgenic mice suggest that Hoxc8 is involved in cell proliferation during cartilage development. In order to directly assess its role in cell proliferation of a specific skeletal cell type, the cartilage-producing chondrocyte, we performed morpholino-mediated knockdown experiments in normal primary chondrocytes. Through analysis of PCNA expression and staining for phosphorylated Histone 3, two cell cycle markers, we show that interference with Hoxc8 expression in chondrocytes reduces cell proliferation, but in the absence of apoptosis. Instead, cells with a knockdown in Hoxc8 expression appear to be delayed in their progression through the cell cycle. Our results provide evidence for prolonged duration of and delayed exit from M-phase, thus implicating a role for Hoxc8 in controlling cell cycle progression at this critical check point.
authors.affiliation: Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198-5805, USA.
authors.forename: Suzan
authors.initials: S
authors.lastname: Kamel
authors.forename: Claudia
authors.initials: C
authors.lastname: Kruger
authors.forename: J Michael
authors.initials: JM
authors.lastname: Salbaum
authors.forename: Claudia
authors.initials: C
authors.lastname: Kappen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009025:Morpholines; D009841:Oligonucleotides; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D018398:Homeodomain Proteins; C489816:Hoxc8 protein, mouse; D009025:Morpholines; D009841:Oligonucleotides; D018809:Proliferating Cell Nuclear Antigen