Interleukin-1 receptor-like proteins synthesized by translation, in vitro, of immunopurified polysomal messenger RNA.
Interleukin-1 (IL-1) receptors can be solubilized from murine cell surfaces and immunoprecipitated with a xenogeneic rat antiserum raised in this laboratory. We demonstrated first that this antiserum contains antibodies directed against IL-1 receptors. We have now successfully used this antiserum as a reagent to immunopurify polysomes along with their messenger RNA from a murine leukemic cell line known to express relatively high levels of IL-1 receptors. The immunoselected mRNA was translated into proteins in vitro. The translation products contained an IL-1 binding protein which could specifically bind to immobilized IL-1 but not to other immobilized ligands such as interleukin-2 or tumor necrosis factor-alpha. The translation products which bound to IL-1 could be acid-eluted from the immobilized ligand, and the proteins released could still specifically bind to IL-1 in a receptor-ligand binding reaction. The eluted IL-1 binding proteins, as well as soluble receptor-ligand complexes derived from them, could also be immunoprecipitated with the xenogeneic rat antiserum. The xenogeneic rat antiserum could, furthermore, immunoprecipitate the IL-1 binding proteins from the translated products before ligand was added. The residual translated products no longer interacted with IL-1. We conclude that our antiserum contains antibodies that recognize determinants expressed on the following proteins: on nascent chains of IL-1 binding proteins; on soluble translated IL-1 binding proteins; on soluble complexes of IL-1 binding proteins that had been cross-linked with IL-1 ligand; and on cell surface-associated IL-1 receptors. The translated and unprocessed IL-1 binding proteins have a molecular mass of approximately 52,000-56,000 daltons.
Rangnekar
V M
VM
Department of Internal Medicine, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612.
Plate
J M
JM
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D007375:Interleukin-1 / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D011132:Polyribosomes / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000235:genetics*; D017472:Receptors, Interleukin-1; D013945:Thymoma / Q000276:immunology; D013953:Thymus Neoplasms / Q000276:immunology
D007375:Interleukin-1; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1