Slow response variant of the B lymphoma 70Z/3 defective in LPS activation of NF-kappa B.
The mouse B cell lymphoma 70Z/3 is membrane immunoglobulin M (mIgM) negative, but treatment of the cells with bacterial lipopolysaccharide (LPS) induces the expression of kappa (kappa) light chain synthesis, and the cells become mIgM+. In wild type cells, this reaction is maximal after 24 h; we have isolated a variant, 1B8, which becomes mIgM+ only after a more prolonged incubation with LPS. This delayed response results from a reduced rate of accumulation of (kappa) mRNA and protein. The transcription factor, NF-kappa B is present in the cytoplasm of both the wild type and the variant cells in its inactive form. The delay in kappa expression is correlated with the failure of NF-kappa B to be activated and translocated to the nucleus. Although NF-kappa B cannot be activated by LPS, it can be activated by treatment with phorbol ester (PMA). In contrast to the clear defect in NF-kappa B, LPS treatment of 1B8 cells causes the octamer-binding factor OTF-2 to increase normally. We conclude that the defect in 1B8 cells is in an early part of the LPS activation pathway, prior to the activation of NF-kappa B, but after the signal for OTF-2 induction. The phenotype of 1B8 demonstrates that an increase in OTF-2 alone is sufficient to cause a large increase in kappa transcription in 70Z/3 cells, but that without NF-kappa B, the response is slow to develop. In this view, NF-kappa B functions to facilitate kappa transcription and to speed its rate of increase, but is not required for the long-term response of 70Z/3 cells to LPS.
Rooney
J W
JW
Department of Genetics SK-50, University of Washington, Seattle 98195.
Emery
D W
DW
Sibley
C H
CH
D000818:Animals; D001402:B-Lymphocytes; D007075:Immunoglobulin M / Q000096:biosynthesis; D007145:Immunoglobulin kappa-Chains / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008223:Lymphoma / Q000235:genetics* / Q000276:immunology; D051379:Mice; D016328:NF-kappa B; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects
D007075:Immunoglobulin M; D007145:Immunoglobulin kappa-Chains; D008070:Lipopolysaccharides; D016328:NF-kappa B; D014157:Transcription Factors; D013755:Tetradecanoylphorbol Acetate