Molecular cloning of 114/A10, a cell surface antigen containing highly conserved repeated elements, which is expressed by murine hemopoietic progenitor cells and interleukin-3-dependent cell lines.
Monoclonal antibody 114/A10, raised against the murine multipotential hemopoietic progenitor cell line B6SUtA, identifies an antigen highly expressed by primary myeloid progenitor cells, the myelomonocytic leukemia cell line WEHI-3, and various interleukin-3 (IL-3)-dependent cell lines. Western blotting studies indicate that the 114/A10 antigen has a mean relative molecular mass of 150,000 but varies greatly in size range between different cell types. cDNA clones encoding this protein were isolated from a plasmid-based expression vector library prepared from B6SUtA RNA. Three clones corresponding in size to the two major mRNA species detected in IL-3-dependent cell lines (3.0 and 2.2 kilobase pairs) and differing in their utilization of alternative polyadenylation signals were obtained. These clones contain a single long open reading frame of 573 amino acids possessing the typical characteristics of an integral membrane protein. A particularly striking feature of this sequence is the presence at the extracellular amino terminus of a series of eight highly conserved 27-amino acid, serine/threonine-rich (55%) tandem repeats that may serve as sites of extensive glycosylation. The extracellular domain also contains three epidermal growth factor-like cysteine-rich repeats. The distribution and structural characteristics of the 114/A10 antigen suggest a possible regulatory role in the cellular response to IL-3.
Dougherty
G J
GJ
Terry Fox Laboratory, British Columbia Cancer Research Centre, Vancouver, Canada.
Kay
R J
RJ
Humphries
R K
RK
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004815:Epidermal Growth Factor / Q000235:genetics; D005786:Gene Expression Regulation; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D007377:Interleukin-3 / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007377:Interleukin-3; C063487:Ly64 protein, mouse; D004815:Epidermal Growth Factor; D004247:DNA