title: Prospective signs of cleidocranial dysplasia in Cebpb deficiency.
abstract: BACKGROUND
  Although runt-related transcription factor 2 (RUNX2) has been considered a determinant of cleidocranial dysplasia (CCD), some CCD patients were free of RUNX2 mutations. CCAAT/enhancer-binding protein beta (Cebpb) is a key factor of Runx2 expression and our previous study has reported two CCD signs including hyperdontia and elongated coronoid process of the mandible in Cebpb deficient mice. Following that, this work aimed to conduct a case-control study of thoracic, zygomatic and masticatory muscular morphology to propose an association between musculoskeletal phenotypes and deficiency of Cebpb, using a sample of Cebpb-/-, Cebpb+/- and Cebpb+/+ adult mice. Somatic skeletons and skulls of mice were inspected with soft x-rays and micro-computed tomography (μCT), respectively. Zygomatic inclination was assessed using methods of coordinate geometry and trigonometric function on anatomic landmarks identified with μCT. Masseter and temporal muscles were collected and weighed. Expression of Cebpb was examined with a reverse transcriptase polymerase chain reaction (RT-PCR) technique.
  
  
  RESULTS
  Cebpb-/- mice displayed hypoplastic clavicles, a narrow thoracic cage, and a downward tilted zygomatic arch (p < 0.001). Although Cebpb+/- mice did not show the phenotypes above (p = 0.357), a larger mass percentage of temporal muscles over masseter muscles was seen in Cebpb+/- littermates (p = 0.012). The mRNA expression of Cebpb was detected in the clavicle, the zygoma, the temporal muscle and the masseter muscle, respectively.
  
  
  CONCLUSIONS
  Prospective signs of CCD were identified in mice with Cebpb deficiency. These could provide an additional aetiological factor of CCD. Succeeding investigation into interactions among Cebpb, Runx2 and musculoskeletal development is indicated.
authors.forename: Boyen
authors.initials: B
authors.lastname: Huang
authors.affiliation: Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Shogoin-Kawahara-cho 54, Sakyo-ku, Kyoto 606-8507, Japan. takahask@kuhp.kyoto-u.ac.jp.
authors.forename: Katsu
authors.initials: K
authors.lastname: Takahashi
authors.forename: Ernest A
authors.initials: EA
authors.lastname: Jennings
authors.forename: Pongthorn
authors.initials: P
authors.lastname: Pumtang-On
authors.forename: Honoka
authors.initials: H
authors.lastname: Kiso
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Togo
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Saito
authors.forename: Manabu
authors.initials: M
authors.lastname: Sugai
authors.forename: Shizuo
authors.initials: S
authors.lastname: Akira
authors.forename: Akira
authors.initials: A
authors.lastname: Shimizu
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Bessho
mesh_terms: D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000172:deficiency / Q000235:genetics*; D002973:Cleidocranial Dysplasia / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D051379:Mice; D041641:Musculoskeletal Development / Q000235:genetics*; D020125:Mutation, Missense; D010641:Phenotype; D012886:Skull / Q000254:growth & development
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; C545013:Cebpb protein, mouse; D050659:Core Binding Factor Alpha 1 Subunit; C493716:Runx2 protein, mouse