title: Functional analysis of a novel RUNX2 missense mutation found in a family with cleidocranial dysplasia.
abstract: Mutations of the RUNX2 gene result in dominantly inherited cleidocranial dysplasia (CCD). RUNX2 encodes for an osteoblast-specific transcription factor, which recognizes specific DNA sequences by the runt domain. DNA binding is stabilized by the interaction with the protein CBFbeta, which induces structural modifications of the runt domain. A novel 574G > A RUNX2 missense mutation has been found in members of a family clinically diagnosed with CCD. This mutation causes the glycine at position 192 to change to arginine (G192R), in loop 9 of the runt domain. Unlike other residues of loop 9, G192 does not establish DNA contacts. Accordingly, the G192R mutant showed a 50% reduction in binding activity compared to the wild-type runt domain. However, the mutation completely abolished the activating properties of the protein on osteocalcin promoter. Moreover, the G192R mutant exerts a dominant-negative effect when overexpressed. Computer modeling indicated that the G192R mutation perturbs not only loop 9, but also other parts of the runt domain, suggesting impairment of the interaction with CBFbeta.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, Piazzale Kolbe 1, 33100 Udine, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Puppin
authors.forename: Lucia
authors.initials: L
authors.lastname: Pellizzari
authors.forename: Dora
authors.initials: D
authors.lastname: Fabbro
authors.forename: Federico
authors.initials: F
authors.lastname: Fogolari
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tell
authors.forename: Alessanda
authors.initials: A
authors.lastname: Tessa
authors.forename: Filippo M
authors.initials: FM
authors.lastname: Santorelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Damante
mesh_terms: D000328:Adult; D002973:Cleidocranial Dysplasia / Q000209:etiology / Q000235:genetics*; D050659:Core Binding Factor Alpha 1 Subunit / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D005260:Female; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D020125:Mutation, Missense; D010641:Phenotype; D014158:Transcription, Genetic
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C493709:RUNX2 protein, human