DEVELOPMENT OF CHICKEN AORTIC SMOOTH-MUSCLE - EXPRESSION OF CYTOSKELETAL AND BASEMENT-MEMBRANE PROTEINS DEFINES 2 DISTINCT CELL PHENOTYPES EMERGING FROM A COMMON LINEAGE

We describe our studies on the characterization of the cell phenotypes in the wall of the aortic-arch-derived arteries from ''late'' chicken embryos, Using immunocytochemistry with antibodies against smooth mus cle cytoskeletal and basement membrane proteins, we show that the smoo th muscle of the aortic-arch-derived arteries from 13- to 19-d-old emb ryos contains two cell phenotypes organized in interchanging lamellae. One cell phenotype (lamellar cells), but not the other cell phenotype (interlamellar cells), expresses the cytoskeletal proteins desmin and alpha smooth muscle actin (alpha SMactin). Both cell phenotypes expre ss the cytoskeletal protein vimentin, Furthermore, the lamellar cells but not the interlamellar cells are surrounded by the basement membran e proteins laminin and collagen type IV. Performing quail-chick transp lantation experiments and using a quail specific antibody, we show tha t both lamellar and interlamellar cells in the ''aortic arches'' of a 15-d-old chimeric embryo are derived from neural crest cells, We concl ude that the aortic smooth muscle cells from ''late'' chicken embryos consist of two distinct cell phenotypes which are derived from a commo n lineage.