Cloning and characterization of a mouse IL-12 receptor-beta component

J Immunol. 1995 Nov 1;155(9):4286-94.

Abstract

Using DNA cross-hybridization, we have isolated and characterized cDNA clones encoding a mouse (mo) IL-12R beta component. Two forms of cDNA were found. The first form encodes a receptor protein that has an overall structure very similar to that of the known human (hu) IL-12R beta with 54% amino acid identity, whereas in the second type of mouse cDNA, the equivalent of the transmembrane region has been deleted. This presumed alternative splicing event also gives rise to a frame shift that results in a receptor with an identical extracellular domain but a different C-terminal sequence. Whether this alternative C terminus is capable of signaling is not yet known. Both types of receptors when expressed in COS-7 cells are membrane associated and bind moIL-12 with an affinity of 1 nM, similar to the affinity of huIL-12R beta for huIL-12. The monomeric size of both moIL-12R beta proteins is about 100 kDa. Similar to huIL-12R beta, moIL-12R beta is expressed at the surface of COS-7 and Ba/F3 cells as a dimer/oligomer whose formation is independent of IL-12 binding. When expressed in Ba/F3 cells, moIL-12R beta binds moIL-12 with two affinities of 50 and 470 pM, corresponding to the medium and high affinity IL-12 binding sites previously identified on mouse Con A lymphoblasts. Despite the higher affinity displayed by the moIL-12R beta in Ba/F3 cells, this receptor alone is not sufficient to transduce a signal, suggesting that another subunit is probably required to generate a functional moIL-12R complex.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Western
  • Cloning, Molecular
  • DNA, Complementary / isolation & purification
  • Female
  • Genomic Library
  • Humans
  • Interleukin-12 / immunology
  • Interleukin-12 / metabolism
  • Macromolecular Substances
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Precipitin Tests
  • Protein Binding
  • RNA, Messenger / analysis
  • Rats
  • Rats, Inbred Lew
  • Receptors, Interleukin / chemistry
  • Receptors, Interleukin / genetics*
  • Receptors, Interleukin / isolation & purification*
  • Receptors, Interleukin-12

Substances

  • DNA, Complementary
  • Il12rb2 protein, rat
  • Macromolecular Substances
  • RNA, Messenger
  • Receptors, Interleukin
  • Receptors, Interleukin-12
  • Interleukin-12

Associated data

  • GENBANK/U23922