CADHERIN-11 EXPRESSED IN ASSOCIATION WITH MESENCHYMAL MORPHOGENESIS IN THE HEAD, SOMITE, AND LIMB BUD OF EARLY MOUSE EMBRYOS

Cadherin-11 (cad-11) is a novel member of the cadherin family of cell adhesion molecules, having recently been identified by means of the po lymerase chain reaction. To study the function and expression of this molecule, we cloned mouse cad-11 cDNA. Transfection of L cells with cD NA led them to acquire a typical cadherin-dependent cell-cell adhesive ness, and the L cells expressing cad-11 did not coaggregate with L cel ls expressing E-, P-, N-, or R-cadherin when they were mixed, indicati ng that this novel cadherin has a hemophilic binding specificity, as f ound for other cadherins. To determine the developmental expression pa ttern of this molecule, we performed in situ hybridization analysis on early mouse embryos. Cad-11 first appeared in mesodermal layers only in the head and tail regions at the mid-to-late primitive streak stage s. In the head, this appearance was followed by strong expression in m esenchymal tissues including branchial arches. In the trunk, the parax ial mesoderm initially did not express cad-11. However, as the somites formed, they expressed cad-11, and this expression was strictly corre lated with their initial condensation and segregation from the presomi tic mesoderm. The cad-11 expression in the somites was eventually rest ricted to sclerotome cells. As the limb buds developed, cad-11 appeare d in the distal portion of the limb mesenchyme, and, at later stages, its expression was most evident at the peripheral mesenchyme. Cad-11 w as thus expressed by restricted populations of mesenchymal cells in ea rly embryos, although it was also expressed in parts of the neural tub e, such as the optic vesicle and dorsal midline, and in part of the ot ic vesicle. As a step to investigate the role of cad-11 in mesenchymal cell adhesion, we dissociated the limb bud mesenchyme into single cel ls, pelleted them, and cultured them as aggregates. In these cultures, cad-11-positive cells clearly sorted out of the negative cell populat ion, suggesting that cad-11 might be involved in selective association of mesenchymal cells. For comparison, we studied the expression of N- cadherin and found that the expressions of these two cadherins were di fferential, and complementary in some tissues. These results suggest t hat cad-11 is involved in specific associations of subsets of mesenchy mal cells and also of some neural cells during early embryogenesis. (C ) 1995 Academic Press, Inc.