title: Expression of a gene encoding a unique protein-tyrosine kinase within specific fetal- and adult-derived hematopoietic lineages.
abstract: A gene encoding a unique protein-tyrosine kinase was isolated by PCR from undifferentiated embryonic stem (ES) cells. The gene, Emsk (embryonic stem cell kinase), is expressed in a number of different lymphoid and myeloid hematopoietic lineages and has been shown to be identical to the recently isolated focal adhesion-associated kinase gene (Fadk). Within the nonlymphoid lineages analyzed, Emsk/Fadk was found to be expressed in primitive and definitive erythroid cells but not in mast cells or macrophages. All CD5+ (B-1a) B cells tested, as well as freshly isolated conventional (B-2) B cells, expressed readily detectable levels of Emsk/Fadk. Within the T-cell lineage, Emsk/Fadk was expressed in V gamma 5 gamma/delta cells as well as in immature alpha/beta cells found within the thymus. As the alpha/beta T-cell population matures and exits the thymus, expression of Emsk/Fadk appears to be down regulated. The expression pattern outlined here suggests a role for Emsk/Fadk in multiple stages of hematopoietic development and raises the possibility that the kinase encoded by this gene has a broader spectrum of activities than was initially suggested.
authors.affiliation: Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.
authors.forename: K
authors.initials: K
authors.lastname: Choi
authors.forename: M
authors.initials: M
authors.lastname: Kennedy
authors.forename: G
authors.initials: G
authors.lastname: Keller
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000201:enzymology; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D017124:Conserved Sequence; D004247:DNA / Q000302:isolation & purification; D005333:Fetus; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000201:enzymology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger; D013154:Spleen / Q000201:enzymology; D013234:Stem Cells / Q000201:enzymology*; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology*
chemical_list: D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D004247:DNA; D011505:Protein-Tyrosine Kinases