Molecular cloning and chromosomal mapping of a candidate cytokine gene selectively expressed in human CD34+ cells.
A rare population of human bone marrow (BM) and cord blood (CB) mononuclear cells bearing the CD34 surface marker (CD34+) function as hematopoietic stem/progenitor cells. Cells lacking CD34 expression (CD34-) in BM and CB are largely mature hematopoietic cells of various lineages that are derived from the CD34+ cells. To elucidate molecular mechanisms governing functional differences between CD34+ and CD34- hematopoietic cells, we used representational difference analysis (RDA)-based subtraction to identify genes that are specifically or preferentially expressed in CD34+ cells. Among the 73 RDA fragments initially sequenced, 30% are derived from the CD34 and c-kit genes that are preferentially expressed in CD34+ cells. An additional 27 (37%) are novel or homologous only to entries in expressed sequence tag databases. One (C17) was found four times and is expressed in CD34+ but not in CD34- cell populations from CB or BM. The cloned C17 cDNA encodes a novel polypeptide of 136 amino acids with a signal sequence. No homology to this peptide was found in the public databases. A secondary-structure analysis predicts that the C17 peptide contains four alpha-helices, a characteristic of hematopoietic cytokines and interleukins. This novel gene is mapped to human chromosome 4p15-p16.
Liu
X
X
Osiris Therapeutics, Inc., Baltimore, Maryland 21231, USA.
Rapp
N
N
Deans
R
R
Cheng
L
L
D000595:Amino Acid Sequence; D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis*; D001483:Base Sequence; D001798:Blood Proteins; D001854:Bone Marrow Cells / Q000378:metabolism; D002874:Chromosome Mapping; D002894:Chromosomes, Human, Pair 4; D003001:Cloning, Molecular; D006224:Cricetinae; D016207:Cytokines / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D005312:Fetal Blood / Q000166:cytology; D018507:Gene Expression Regulation, Developmental; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization / Q000379:methods; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D018952:Antigens, CD34; D001798:Blood Proteins; C412483:CYTL1 protein, human; D016207:Cytokines; D018076:DNA, Complementary; D011994:Recombinant Proteins