title: GAS6, the ligand of Axl and Rse receptors, is expressed in hematopoietic tissue but lacks mitogenic activity.
abstract: GAS6, a gene previously identified as growth arrest specific, has been demonstrated to be the ligand of Axl, a novel tyrosine kinase receptor widely expressed in both normal and neoplastic hematopoietic tissue. We have observed previously that GAS6 mRNA was present in whole bone marrow. This preliminary finding prompted us to investigate the presence of GAS6 in hematopoietic tissue and the possible role of this molecule in controlling the proliferation of hematopoietic precursors. We report here that the protein GAS6 is diffusely present in hematopoietic tissue, both in stromal and in hematopoietic cells, and that, among these cells, positivity is observed in megakaryocytes and myelomonocytic precursors. Furthermore, our data suggest that GAS6 is not a growth factor for hematopoietic progenitors or stromal fibroblasts. Despite the fact that both the Axl receptor and its ligand, GAS6, are expressed in hematopoietic tissue, the biological role of their interactions remains to be determined.
authors.affiliation: Dipartimento di Scienze Mediche, Facoltà di Medicina di Novara, Italy.
authors.forename: G C
authors.initials: GC
authors.lastname: Avanzi
authors.forename: M
authors.initials: M
authors.lastname: Gallicchio
authors.forename: G
authors.initials: G
authors.lastname: Cavalloni
authors.forename: L
authors.initials: L
authors.lastname: Gammaitoni
authors.forename: F
authors.initials: F
authors.lastname: Leone
authors.forename: A
authors.initials: A
authors.lastname: Rosina
authors.forename: R
authors.initials: R
authors.lastname: Boldorini
authors.forename: G
authors.initials: G
authors.lastname: Monga
authors.forename: L
authors.initials: L
authors.lastname: Pegoraro
authors.forename: B
authors.initials: B
authors.lastname: Varnum
authors.forename: M
authors.initials: M
authors.lastname: Aglietta
mesh_terms: D001706:Biopsy; D001854:Bone Marrow Cells / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology; D015870:Gene Expression; D006410:Hematopoiesis; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008934:Mitogens; D015513:Oncogene Proteins / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology; D011994:Recombinant Proteins / Q000494:pharmacology; D000094963:Axl Receptor Tyrosine Kinase; D000099255:Growth Arrest-Specific Protein 6
chemical_list: D016298:Hematopoietic Cell Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008934:Mitogens; D015513:Oncogene Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D020794:Receptor Protein-Tyrosine Kinases; D011994:Recombinant Proteins; D000094963:Axl Receptor Tyrosine Kinase; D000099255:Growth Arrest-Specific Protein 6; C084944:TYRO3 protein, human; C000722289:AXL protein, human