The Dtk receptor tyrosine kinase, which binds protein S, is expressed during hematopoiesis.
Dtk (Tyro 3/Sky/Rse/Brt/Tif) belongs to a recently recognized subfamily of receptor tyrosine kinases that also includes Ufo (Axl/Ark) and Mer (Eyk). Ligands for Dtk and Ufo have been identified as protein S and the related molecule Gas6, respectively. This study examined expression of Dtk during ontogeny of the hematopoietic system and compared the pattern of expression with that of Ufo. Both receptors were abundantly expressed in differentiating embryonic stem cells, yolk sac blood islands, para-aortic splanchnopleural mesoderm, fractionated AA4+ fetal liver cells, and fetal thymus from day 14 until birth. Although Ufo was expressed at moderate levels in adult bone marrow, expression of Dtk in this tissue was barely detectable. In adult bone marrow subpopulations fractionated using counterflow centrifugal elutriation, immunomagnetic bead selection for lineage-depletion and FACS sorting for c-kit expression, very low levels of Dtk and/or Ufo were detected in some cell fractions. These results suggest that Dtk and Ufo are likely to be involved in the regulation of hematopoiesis, particularly during the embryonic stages of blood cell development.
Crosier
P S
PS
Department of Molecular Medicine, University of Auckland, New Zealand.
Freeman
S A
SA
Orlic
D
D
Bodine
D M
DM
Crosier
K E
KE
D000818:Animals; D029681:Arabidopsis Proteins; D001483:Base Sequence; D001853:Bone Marrow / Q000201:enzymology; D004622:Embryo, Mammalian / Q000201:enzymology; D004790:Enzyme Induction; D018507:Gene Expression Regulation, Developmental; D006410:Hematopoiesis / Q000502:physiology*; D006413:Hematopoietic System / Q000196:embryology* / Q000201:enzymology / Q000254:growth & development; D036341:Intercellular Signaling Peptides and Proteins; D008099:Liver / Q000196:embryology / Q000201:enzymology; D008648:Mesoderm / Q000201:enzymology; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics; D017293:Protein S / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000201:enzymology; D013950:Thymus Gland / Q000196:embryology / Q000201:enzymology; D014157:Transcription Factors; D015017:Yolk Sac / Q000201:enzymology; D000099255:Growth Arrest-Specific Protein 6
D029681:Arabidopsis Proteins; D036341:Intercellular Signaling Peptides and Proteins; D010940:Plant Proteins; D017293:Protein S; D011506:Proteins; D020794:Receptor Protein-Tyrosine Kinases; D014157:Transcription Factors; D000099255:Growth Arrest-Specific Protein 6; C098247:UFO protein, Arabidopsis; C084944:TYRO3 protein, human