title: Embryonic expression of eph signalling factors in Xenopus.
abstract: Cellular communication in the developing embryo is mediated by receptor-ligand interactions at the cell surface. Receptor protein tyrosine kinases (RTKs) have been shown to play a critical role in the development of the vertebrate embryo. The eph receptors are a large subclass of RTKs for which a corresponding ligand family has only recently been described. The restricted expression patterns of several eph receptors imply roles for these molecules in early vertebrate development. We have isolated both a ligand of the eph ligand family (ELF), that we have named XELF-a, and an eph-related receptor, XE10, the likely homolog of the murine eck/Sek-2 receptor. At least two forms of the XELF-a transcript are present in the developing embryo. A truncated form of the XELF-a ligand, XELF-á, is the first ELF ligand isolated that lacks both the membrane-spanning and membrane-anchoring motifs conserved among this family, suggesting that ELF ligands can function as fully soluble molecules in vivo. XELF-a and XE10 are expressed maternally and throughout early embryogenesis, while XELF-á is only expressed zygotically. The dynamic expression patterns of these signalling molecules, in both mesoderm and neurectoderm, suggest that they may play a role in the patterning of the early vertebrate embryo.
authors.affiliation: Rockefeller University, New York, NY 10021, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Weinstein
authors.forename: S M
authors.initials: SM
authors.lastname: Rahman
authors.forename: J C
authors.initials: JC
authors.lastname: Ruiz
authors.forename: A
authors.initials: A
authors.lastname: Hemmati-Brivanlou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods; D003593:Cytoplasm / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D014981:Xenopus / Q000196:embryology*; D029867:Xenopus Proteins
chemical_list: C104036:EFNA1 protein, Xenopus; D008024:Ligands; D008565:Membrane Proteins; D012333:RNA, Messenger; D029867:Xenopus Proteins; D020794:Receptor Protein-Tyrosine Kinases