Functional murine interleukin 6 receptor with the intracisternal A particle gene product at its cytoplasmic domain. Its possible role in plasmacytomagenesis.
Two species of the cDNAs encoding murine IL-6-R (one is abnormal and the other authentic) have been cloned from a plasmacytoma cell line, P3U1, and BALB/c mouse spleen cDNA libraries. In the cDNA encoding the abnormal IL-6-R, the region corresponding to an intracytoplasmic domain was replaced with a part of the long terminal repeat of the intracisternal A particle gene (IAP-LTR). The authentic IL-6-R consists of 460 amino acids with the domain of the Ig superfamily. The overall homology between murine and human IL-6-R was 69 and 54% at DNA and protein levels, respectively. The extracellular domain after the Ig-like domain of murine IL-6-R was found to have an homology with those of murine erythropoietin R, human IL-2-R beta chain, murine IL-4-R, and human granulocyte-macrophage CSF-R, as in the case of human IL-6-R, and these receptors have been classified as members of the IL receptor family. In P3U1 cells, the expression of the mRNA encoding abnormal IL-6-R was much higher than that of the mRNA encoding authentic IL-6-R. An IL-6-dependent human T cell line, KT-3, which did not respond to murine IL-6, acquired the responsiveness to murine IL-6 when transfected with the cDNA encoding abnormal IL-6-R, indicating that abnormal IL-6-R lacking a normal cytoplasmic domain can function. Since IL-6 functions as a potent growth factor for murine plasmacytomas, over-expression of abnormal IL-6-R may function as a positive selection element for the development of certain plasmacytomas.
Sugita
T
T
Institute for Molecular and Cellular Biology, Osaka University, Japan.
Totsuka
T
T
Saito
M
M
Yamasaki
K
K
Taga
T
T
Hirano
T
T
Kishimoto
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003593:Cytoplasm; D004273:DNA, Neoplasm / Q000235:genetics; D015870:Gene Expression; D015723:Gene Library; D007426:Genes, Intracisternal A-Particle; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010954:Plasmacytoma / Q000235:genetics*; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000235:genetics; D011971:Receptors, Immunologic / Q000235:genetics*; D019947:Receptors, Interleukin-6; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013154:Spleen / Q000166:cytology; D014162:Transfection; D014407:Tumor Cells, Cultured
D004273:DNA, Neoplasm; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D019947:Receptors, Interleukin-6