%0 Journal Article
%T ¦Â-catenin/cyclin D1 mediated development of suture mesenchyme in calvarial morphogenesis
%A Anthony J Mirando
%A Takamitsu Maruyama
%A Jiang Fu
%A Hsiao-Man Yu
%A Wei Hsu
%J BMC Developmental Biology
%D 2010
%I BioMed Central
%R 10.1186/1471-213x-10-116
%X Here we utilize a gain-of-function analysis to further assess the role of ¦Â-catenin. A transgenic expression system permitting conditional activation of ¦Â-catenin in a spatiotemporal specific manner has been developed. Aberrant stimulation of ¦Â-catenin leads to increases in expansion of skeletogenic precursors and the enhancement of bone ossification reminiscent to the loss of Axin2. The constitutively active signal promotes specification of osteoprogenitors, but prevents their maturation into terminally differentiated osteoblasts, along the osteoblast lineage. However, the prevention does not interfere with bone synthesis, suggesting that mineralization occurs without the presence of mature osteoblasts. ¦Â-catenin signaling apparently plays a key role in suture development through modulation of calvarial morphogenetic signaling pathways. Furthermore, genetic inactivation of the ¦Â-catenin transcriptional target, cyclin D1, impairs expansion of the skeletogenic precursors contributing to deficiencies in calvarial ossification. There is a specific requirement for cyclin D1 in populating osteoprogenitor cell types at various developmental stages.These findings advance our knowledge base of Wnt signaling in calvarial morphogenesis, suggesting a key regulatory pathway of Axin2/¦Â-catenin/cyclin D1 in development of the suture mesenchyme.The mammalian skull consists of neurocranium and viscerocranium that are formed from skeletogenic mesenchyme derived from both mesoderm and neural crest [1]. The cranial skeletogenic mesenchyme mainly undergoes intramembranous ossification to form the bone plates [2]. This process differs from endochondral ossification in the appendicular and axial skeletons, which prior formation of cartilage templates is required. The growth of calvaria is then able to accommodate expansion of the brain [2]. During calvarial morphogenesis, cranial sutures serve as skeletogenic growth centers where undifferentiated stem cells develop into calvarial osteopr
%U http://www.biomedcentral.com/1471-213X/10/116