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Establishing the genetic basis that underlies craniofacial variability in natural populations is one of the main topics of evolutionary and developmental studies. One of the genes associated with mammal craniofacial variability is RUNX2, and in the present study we investigated the association between craniofacial length and width and RUNX2 across New World bats (Phyllostomidae) and primates (Catarrhini and Platyrrhini). Our results showed contrasting patterns of association between the glutamate/alanine ratios (Q/A ratio) and palate shape in these highly diverse groups. In phyllostomid bats, we found an association between shorter/broader faces and increase of the Q/A ratio. In New World monkeys (NWM) there was a positive correlation of increasing Q/A ratios to more elongated faces. Our findings reinforced the role of the Q/A ratio as a flexible genetic mechanism that would rapidly change the time of skull ossification throughout development. However, we propose a scenario in which the influence of this genetic adjustment system is indirect. The Q/A ratio would not lead to a specific phenotype, but throughout the history of a lineage, would act along with evolutionary constraints, as well as other genes, as a facilitator for adaptive morphological changes.

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Cleidocranial dysplasia (CCD; MIM 119600) is an autosomal dominant hereditary disorder of skeletal features whose characteristic clinical symptoms are caused by mutations in the RUNX2 gene. Varying degrees of clavicular hypoplasia and dental abnormalities are the most prominent features of this disorder. In this study, we presented a Chinese family that included 4 individuals with a p.R225Q mutation in the RUNX2 gene and characteristic CCD phenotypes. Through structural analysis of the p.R225Q mutation in the RUNX2 protein, we determined that the location of this mutation has the potential to affect DNA binding by RUNX2. The proband in this CCD-affected family showed a specific clinical phenotype of CCD that included a median pseudo-cleft palate, which is a presentation of this mutation that has not been reported previously. On the basis of the structural analysis, this study further demonstrated that the p.R225Q mutation abolished DNA binding by RUNX2 and its results also suggested that other genetic and/or environmental factors could affect the CCD phenotypes.

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Objetivo: No atual trabalho propomo-nos a avaliar morfometricamente possíveis alterações na reparação óssea alveolar pós-exodontia de ratos tratados com Meloxicam, um anti-inflamatório inibidor preferencial da cicloxigenase 2 (COX-2) e correlacionar com a expressão temporal da COX-2 e do fator de transcrição 2 com domínio Runt (Runx-2) associada com a diferenciação de células da linhagem osteoblástica. Material e Métodos: A exodontia do incisivo superior direito foi realizada em 120 ratos Wistar, divididos em grupo controle (n = 60) - animais tratados com injeção intraperitoneal de 0,1 ml de solução salina 0,9% diariamente e grupo tratado (n = 60) animais tratados com injeção de Meloxicam na dose de 3mg/kg de massa corporal, diariamente, ambos durante 7 dias. O volume total do alvéolo (VtA) e do tecido ósseo (VtO), o número de células imunomarcadas/mm² (Nm) para COX-2 e Runx-2 e a expressão protéica por Western blotting (WB) da COX-2 e RUNX-2 foram avaliados nos períodos 3, 7, 10, 14, 21 e 30 dias póscirurgias. Resultados: No grupo tratado o VtA manteve-se constante até os 21 dias, enquanto que no controle foi 0,272 vezes menor em relação aos 3 dias decorrente da maior atividade osteoclástica. Porém, aos 14 dias, no grupo tratado o VtO foi 0,337 vezes menor em relação ao controle decorrente da inibição parcial da transmigração de células inflamatórias responsáveis pela degradação do coágulo e da angiogênese, ocasionando um retardo na formação dos tecidos de granulação/conjuntivo, na diferenciação das células osteoblásticas e na formação/remodelação do tecido ósseo, e consequentemente no reparo ósseo alveolar. A imunomarcação para COX-2 foi observada em diversos tipos celulares, como fibroblastos, células endoteliais, células inflamatórias, osteoblastos e osteócitos. O Nm para COX-2 não apresentou diferenças estatísticas significantes entre os grupos no intervalo de 3 e 21 dias pós-cirurgia, enquanto que, a expressão...

Objective: To evaluate morphometrically possible changes in post-extraction alveolar bone healing in rats treated with Meloxicam, a selective anti-inflammatory inhibitor of cyclooxygenase (COX-2) and to correlate it with the temporal expression of COX-2 and transcription factor 2 with Runt domain (Runx-2) associated with differentiation of osteoblastic lineage cells. Material and Methods: The extraction of the right upper incisor was made in 120 male Wistar rats, divided into control group (n=60) - animals treated with an intraperitoneal injection of 0,1 ml of 0,9% NaCl solution daily for 7 days and the treated group (n=60) - animals treated with injection of 3mg/kg of body weight of Meloxicam 0.9% NaCl solution daily for 7 days. The total alveolar volume (VtA), total bone tissue volume (VtO), number of immunohistochemically positive cells/mm² (Nm) for COX-2 and RUNX-2 and the Western blotting (WB) COX-2 and RUNX-2 protein expressions were evaluated after 3, 7, 10, 14, 21 and 30 days after the surgeries. Results: In the treated group the VtA remained constant until the 21st day, while in the control group at the same day the value was 0,272 times lower compared to the 3 days period, due to the higher osteoclastic activity. However, at 14 days the VtO was 0,337 times lower in the treated group compared to the control due to the partial inhibition of the transmigration of inflammatory cells responsible for the degradation of the clot and angiogenesis, causing a delay in the formation of granulation/connective tissues, differentiation of osteoblastic cells and in bone tissue formation/remodeling, and consequently in the alveolar bone repair. The immunostaining for COX-2 was observed in various cell types, such as fibroblasts, endothelial cells, inflammatory cells, osteoblasts and osteocytes. The Nm for COX-2 showed no statistical differences between groups from the 3rd to the 21st day, while the WB protein expression was on average 0,232 times lower in the...

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We identified a disease-causing mutation of the RUNX2 gene in a four-generation Chinese family affected with cleidocranial dysplasia (CCD). For mutation analysis, the coding region of RUNX2 was sequenced with DNA from two patients and three unaffected family members. The RUNX2 mutation was investigated in 50 normal controls by denaturing high pressure liquid chromatography. A heterozygous single-base deletion (c.549delC) of RUNX2, which predicts a termination site at the 185th codon and leads to a stop in the runt domain of RUNX2 protein, was detected in both patients but not in the three unaffected members of the family. This mutation was also not found in 50 controls and has not been reported previously. We demonstrated that a novel mutation (c.549delC) of RUNX2 is associated with CCD in a Chinese family, adding to the repertoire of RUNX2 mutations related to CCD.

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The Runx2 transcription factor is a key regulator of osteoblast differentiation. In response to 1alpha,25 dihydroxy vitamin D3, Runx2 may interact with the 1alpha,25 dihydroxy vitamin D3 receptor (VDR) in the promoter of target genes, producing a synergic activation of their transcription. Previous studies have suggested that the motifs responsible for the VDR-Runx2 interaction are contained within the 230-361 domain of Runx2. In this work, we confirmed by GST-pull down that Runx2(I(209-361)) is sufficient to interact with the VDR. To obtain structural information, GST-Runx2(I(209-361)) protein was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapor-diffusion method and polyethyleneglycol as a precipitant. The crystals were found to diffract to a maximum resolution of 2.7 A and a complete data set to a 3.3 A resolution was collected and analyzed. The crystals belong to the tetragonal system, with a space group P4 and unit-cell parameters of a = b = 90.8, and c = 57.2 A. The presence of a monomer of the recombinant GST-Runx2(I(209-361)) in the asymmetric unit gives a V(M) of 2.7 A(3) Da(-1) and a solvent content of 54.8%.

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