The mouse homolog of DGCR2 gene encoding within 22q11.2 contributes to enchondral ossification in skull base and its defect causes the severity in 22q11.2 deletion syndrome
After weaning, approximately 50% of Dgcr2-KO mice showed mild skeletal abnormalities with flat face. As shown in Figure 1, the skull base in the Dgcr2-KO mice showed dysplasia caused by earlier defect of synchondrodial joint. Histological analysis of skull base showed that abnormalities in enchondral ossification, especially in hypertrophic chondrocytes, whose sparseness was observed already in one week after birth. The knock-in EGFP was expressed in the decreased hypertrophic chondrocytes in Dgcr2-KO mice. However, heterozygous Dgcr2-KO mice showed no obvious phenotype as in the case of Tbx1 knockout mice.
We generated the heterozygous mutant for both Dgcr2 and Df1, and examined the phenotype, as shown in Figure 2. As in the case of homozygous Dgcr2-KO mice, the double hetero mice showed maxillofacial abnormalities and skull base malformation caused by defects in enchondral ossification, suggesting Dgcr2 together with Tbx1 and molecule(s) expressed within 22q11.2 play an important role in maxillofacial development.
Journal of Oral and Maxillofacial Surgery 76 (10), e71-e72, 2018.
We also presented above data in 100th AAOMS annual meeting (Chicago).
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