TY - JOUR
T1 - Relationship between novel isoforms, functionally important domains, and subcellular distribution of CD164/endolyn
AU - Chan, James Yi Hsin
AU - Lee-Prudhoe, Jane E.
AU - Jorgensen, Britt
AU - Ihrke, Gudrun
AU - Doyonnas, Regis
AU - Zannettino, Andrew C.W.
AU - Buckle, Veronica J.
AU - Ward, Christopher J.
AU - Simmons, Paul J.
AU - Watt, Suzanne M.
PY - 2001/1/19
Y1 - 2001/1/19
N2 - Functional analyses have indicated that the human CD164 sialomucin may play a key role in hematopoiesis by facilitating the adhesion of human CD34+ cells to the stroma and by negatively regulating CD34+CD3810/- cell proliferation. We have identified three novel human CD164 variants derived by alternative splicing of bona fide exons from a single genomic transcription unit. The predominant CD164(E1-6) isoform, encoded by six exons, is a type I transmembrane protein containing two extracellular mucin domains (I and II) interrupted by a cysteine-rich non-mucin domain. The 103B2/9E10 and 105A5 epitopes, which specify ligand binding characteristics, are located on the exon 1-encoded mucin domain I. Three human CD164(E1-6) mRNA species, exhibiting differential polyadenylation site usage, are differentially expressed in hematopoietic and non-hematopoietic tissues. This study provides additional evidence that human CD164(E1-6) represents the ortholog of murine MGC-24v and rat endolyn. Comparative analysis of murine MGC-24v/CD164(E1-6) with human CD164(E1-6) revealed two potential splice variants and a similar genomic structure. Whereas the human CD164 gene is located on chromosome 6q21, the mouse gene occurs in a syntenic region on chromosome 10B1-B2. By confocal microscopy, human CD164 in CD34+CD38+ hematopoietic progenitor (KG1B) and epithelial cell lines appears to be localized primarily in endosomes and lysosomes, with low concentrations at the cell surface. However, in a minority of KG1B cells, CD164 is more prominently expressed at the plasma membrane and in the recycling endosomes, suggesting that its distribution is regulated in cells of hematopoietic origin.
AB - Functional analyses have indicated that the human CD164 sialomucin may play a key role in hematopoiesis by facilitating the adhesion of human CD34+ cells to the stroma and by negatively regulating CD34+CD3810/- cell proliferation. We have identified three novel human CD164 variants derived by alternative splicing of bona fide exons from a single genomic transcription unit. The predominant CD164(E1-6) isoform, encoded by six exons, is a type I transmembrane protein containing two extracellular mucin domains (I and II) interrupted by a cysteine-rich non-mucin domain. The 103B2/9E10 and 105A5 epitopes, which specify ligand binding characteristics, are located on the exon 1-encoded mucin domain I. Three human CD164(E1-6) mRNA species, exhibiting differential polyadenylation site usage, are differentially expressed in hematopoietic and non-hematopoietic tissues. This study provides additional evidence that human CD164(E1-6) represents the ortholog of murine MGC-24v and rat endolyn. Comparative analysis of murine MGC-24v/CD164(E1-6) with human CD164(E1-6) revealed two potential splice variants and a similar genomic structure. Whereas the human CD164 gene is located on chromosome 6q21, the mouse gene occurs in a syntenic region on chromosome 10B1-B2. By confocal microscopy, human CD164 in CD34+CD38+ hematopoietic progenitor (KG1B) and epithelial cell lines appears to be localized primarily in endosomes and lysosomes, with low concentrations at the cell surface. However, in a minority of KG1B cells, CD164 is more prominently expressed at the plasma membrane and in the recycling endosomes, suggesting that its distribution is regulated in cells of hematopoietic origin.
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U2 - 10.1074/jbc.M007965200
DO - 10.1074/jbc.M007965200
M3 - Article
C2 - 11027692
AN - SCOPUS:0035910558
SN - 0021-9258
VL - 276
SP - 2139
EP - 2152
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 3
ER -