title: Regulated expression of the Eph-related receptor tyrosine kinase Hek11 in early human B lymphopoiesis.
abstract: Members of the large Eph family of receptor tyrosine kinases (RTKs) display temporally and spatially restricted expression patterns during embryogenesis, suggesting a role in various developmental processes. We have begun to investigate the expression of members of this receptor family during human hematopoiesis, in particular B lymphopoiesis. Expression of Eph RTKs in cells of the B-lymphoid lineage was assessed by using degenerate oligonucleotide primers based on stretches of conserved nucleic acid sequences in members of the Eph family. First, the content of Eph-family RTKs was assessed in freshly sorted fetal bone marrow pro-B cells. This population was found to harbor transcripts of the Hek8 and Hek11 members of this gene family. Subsequent analysis of expression of these genes in B cells representing various differentiation and ontogenic stages showed that the Hek8 transcript is constitutively present in all fetal and adult B-lineage cells, with high levels of expression in peripheral blood B cells. In contrast, the Hek11 transcript was exclusively found in fetal bone marrow pro-B cells and pre-B cells, but not in more mature fetal B-lineage cells. All adult B-lineage cells, from early pro-B cells to end-stage plasma cells, lacked Hek11 transcripts. The developmentally regulated expression of Hek11 during fetal B lymphopoiesis suggests a role for this gene in pre/pro-B cell expansion and/or differentiation and defines a difference in progenitor B cell populations isolated from fetal versus adult human bone marrow.
authors.affiliation: Department of Immunology, University Hospital Utrecht, Heidelberglaan Utrecht, The Netherlands.
authors.forename: H C
authors.initials: HC
authors.lastname: Aasheim
authors.forename: L W
authors.initials: LW
authors.lastname: Terstappen
authors.forename: T
authors.initials: T
authors.lastname: Logtenberg
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000166:cytology / Q000201:enzymology*; D002454:Cell Differentiation; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D011247:Pregnancy; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D036121:Receptor, EphA3
chemical_list: D020794:Receptor Protein-Tyrosine Kinases; D036121:Receptor, EphA3