Molecular mechanisms of cell adhesion corresponding to positional values in limb bud

点击翻译按钮获取中文摘要

In vertebrate limb development, limb mesenchyme cells in the progress zone form cartilage pattern depending on the positional values allotted to them. The limb bud cells are though to use cell surface molecules to recognize the positional values of their surrounding cells.We have found the difference in cell surface molecules from the cell sorting experiment using chick limb mesenchyme with different positional values. The sorting out in monolayr culture occurred when the mesenchymal cells at different developmental stages or from different positions were mixed. The sorting out occurred independently of chondrogenic potency and cartilage nodules were formed in the center of each sorted area. The mesenchymal cells with different positional values were sorted even on agar where cells could not attach and form aggregates, suggesting the sorting out occurs depending on the difference on not cell-substratum but cell-cell affinity.To identify cell adhesion molecules which control the positional value-related cell adhesion, we first cloned cDNA of cadherin superfamily genes expressing in chick limb bud with RT-PCR.Protocadherin 2, a homologue of human protocadherin Pcdh2, was identified. The expression pattern of protocadherin 2 suggests its close relationship to cell sorting.We have raisd a monoclonal antibody to the cell surface molecular of chick limb bud mesenchyme, which inhibited the sorting out between the progress zone cells at different developmental stages.