Do Peanut Agglutinin Receptors on Somites Control the Behavior of Neural Cells?

Abstract
Peanut agglutinin (PNA) receptors are expressed in the caudal halves of sclerotomes in chick embryos after 3 days of incubation (stages 19-20 of Hamburger and Hamilton). The neural crest cells forming dorsal root ganglia (DRG) and motor nerves appear to avoid PNA positive regions and concentrate into rostral halves of sclerotomes. To investigate the role of PNA receptors in gangliogenesis and nerve growth, we examined PNA binding ability in quail sclerotomes and in chick-quail chimeric embryos made by transplanting quail somites to chick embryos, comparing the development of DRG, motro nerves and sclerotomes. PNA did not bind to any part of the somiles of 4.5-day quail embryos, although dorsal root ganglia and motor nerves appeared only in the rostral halves of sclerotomes as in chick embryos. Moreover, in spite of no PNA binding ability of the transplanted quail somite in 4.5-day chick-quail chimeric embryos, DRG and motor nerves derived from chick tissues appeared only in the rostral halves of the sclerotomes derived from these somites. Thus, both quail and chick neural crest cells and motor nerves recognized the difference between the rostral and caudal halves of sclerotomes of quail embryos in the absence of PNA binding ability, indicating that PNA binding site on somite cells does not support the selective neural crest migration and nerve growth.