title: The gene encoding the stem cell antigen, CD34, is conserved in mouse and expressed in haemopoietic progenitor cell lines, brain, and embryonic fibroblasts.
abstract: The human haemopoietic cell surface antigen, CD34, is a 105 - 120 kd cell surface glycoprotein whose stage-specific expression by stem cells and lineage-specific progenitor cells suggests a role in regulating early events in blood cell differentiation. A murine gene and cDNA encoding a closely homologous protein have been isolated. The gene is organized in eight exons in 22 kb of DNA. The first exon lies in a GC- and CpG-rich island. The sequence of the gene and the cDNA predict a 382 amino acid-long protein containing an N-terminal signal peptide and one transmembrane region 73 amino acids from the C-terminus. The extracellular part of the protein contains: a 140 amino acid-long-N-terminal region, 40% of whose residues are serine or threonine potential attachment sites for O-linked carbohydrate, as well as five potential attachment sites for N-linked carbohydrate. Proximal to the extracellular membrane there is a 79 amino acid-long cysteine-rich region. The homology with the human sequence is highest in the intracellular domain (90% amino acid identity) and lowest in the N-terminal region (43% amino acid identity). The protein is not homologous with any other proteins currently in the databases. The expression of the murine gene by a number of haemopoietic progenitor cell lines suggests that the CD34 function in haemopoiesis may be conserved between man and mouse. The high level of expression in a number of embryonic fibroblast cell lines and in brain imply a function outside of haemopoiesis.
authors.affiliation: Leukaemia Research Fund Centre, Institute of Cancer Research, Chester Beatty Laboratories, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Brown
authors.forename: M F
authors.initials: MF
authors.lastname: Greaves
authors.forename: H V
authors.initials: HV
authors.lastname: Molgaard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018952:Antigens, CD34; D000943:Antigens, Differentiation / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000378:metabolism; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012313:RNA / Q000032:analysis / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid
chemical_list: D018952:Antigens, CD34; D000943:Antigens, Differentiation; D012313:RNA; D004247:DNA