Activity of the kappa B enhancer of the interleukin-2 receptor alpha chain in somatic cell hybrids is accompanied by the nuclear localization of NF-kappa B.
The two nuclear proteins NF-kappa B (consisting of subunits p50 an dp65) and the DNA-binding subunit of NF-kappa B (p50) by itself, also called KBF1, are constitutively expressed and localized in the nucleus of the human T-cell line IARC 301.5. In order to define the roles of these two factors, which bind to the same kappa B enhancers, in transcription activation we have prepared somatic cell hybrids between IARC 301.5 and a murine myeloma. Most hybrids express both KBF1 and NF-kappa B in their nuclei, but one hybrid expresses only KBF1. The kappa B enhancer of the gene encoding the interleukin-2 (IL-2) receptor alpha chain (IL-2R alpha) is functional only in the hybrids expressing nuclear NF-kappa B. These findings show that nuclear NF-kappa B is necessary to activate the kappa B enhancer, while KBF1 by itself is not sufficient. We propose that KBF1 is a competitive inhibitor of NF-kappa B and discuss how these factors may be involved in the transient expression of IL-2 and IL-2R alpha genes during the immune response.
Hémar
A
A
Unité de Génétique Somatique, Institut Pasteur, Paris, France.
Barrand
P
P
Ferrer
M
M
Cornet
V
V
Buttin
G
G
Dautry-Varsat
A
A
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000502:physiology*; D003600:Cytosol / Q000502:physiology; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D006801:Humans; D006822:Hybrid Cells / Q000502:physiology; D046911:Macromolecular Substances; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D015375:Receptors, Interleukin-2 / Q000235:genetics*; D013601:T-Lymphocytes; D014158:Transcription, Genetic
D046911:Macromolecular Substances; D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D015375:Receptors, Interleukin-2