Related Experiment Videos
The Dtk receptor tyrosine kinase, which binds protein S, is expressed during hematopoiesis
P S Crosier1, S A Freeman, D Orlic
1Department of Molecular Medicine, University of Auckland, New Zealand.
Abstract:
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.
Insights
Tyro 3/Sky/Rse/Brt/Tif (Dtk) and Ufo (Axl/Ark) receptor tyrosine kinases are crucial for embryonic hematopoiesis. Their expression significantly decreases in adult bone marrow, suggesting a specialized role in early blood cell development.
Area of Science:
- Hematology
- Molecular Biology
- Developmental Biology
Background:
- The Tyro 3, Axl, Mer (TAM) receptor tyrosine kinase subfamily, including Dtk and Ufo, plays roles in cell signaling.
- Protein S and Gas6 are identified ligands for Dtk and Ufo, respectively.
- Understanding the expression patterns of these receptors is key to elucidating their function in hematopoiesis.
Purpose of the Study:
- To investigate the expression profile of Dtk during the ontogeny of the hematopoietic system.
- To compare the expression pattern of Dtk with that of Ufo throughout hematopoietic development.
- To determine the potential roles of Dtk and Ufo in regulating blood cell formation.
Main Methods:
- Analysis of Dtk and Ufo expression in various embryonic and adult hematopoietic tissues.
- Utilizing techniques such as flow cytometry and cell sorting for detailed analysis of bone marrow subpopulations.
- Examining expression in differentiating embryonic stem cells, yolk sac blood islands, fetal liver, and thymus.
Main Results:
- Both Dtk and Ufo were highly expressed in embryonic hematopoietic tissues, including stem cells, yolk sac, fetal liver, and thymus.
- Ufo showed moderate expression in adult bone marrow, whereas Dtk expression was minimal.
- Low levels of Dtk and/or Ufo were detected in specific adult bone marrow subpopulations.
Conclusions:
- Dtk and Ufo are significantly involved in embryonic hematopoiesis.
- Their expression patterns suggest a critical role during early blood cell development.
- The diminished expression in adult bone marrow indicates a specialized function in developmental stages rather than adult homeostasis.