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Mol. Cell. Biol., 05 1996, 2341-2349, Vol 16, No. 5
JF Klement, NR Rice, BD Car, SJ Abbondanzo, GD Powers, PH Bhatt, CH Chen, CA Rosen and CL Stewart
The ubiquitous transcription factor NF-kappaB is an essential component in
signal transduction pathways, in inflammation, and in the immune response.
NF-kappaB is maintained in an inactive state in the cytoplasm by
protein-protein interaction with IkappaBalpha. Upon stimulation, rapid
degradation of IkappaBalpha allows nuclear translocation of NF- kappaB. To
study the importance of IkappaBalpha in signal transduction,
IkappaBalpha-deficient mice were derived by gene targeting. Cultured
fibroblasts derived from IkappaBalpha-deficient embryos exhibit levels of
NF-kappaB1, NF-kappaB2, RelA, c-Rel, and IkappaBbeta similar to those of
wild-type fibroblasts. A failure to increase nuclear levels of NF-kappaB
indicates that cytoplasmic retention of NF-kappaB may be compensated for by
other IkappaB proteins. Treatment of wild-type cells with tumor necrosis
factor alpha (TNF-alpha) resulted in rapid, transient nuclear localization
of NF-kappaB. IkappaBalpha-deficient fibroblasts are also TNF-alpha
responsive, but nuclear localization of NF-kappaB is prolonged, thus
demonstrating that a major irreplaceable function Of IkappaBalpha is
termination of the NF-kappaB response. Consistent with these observations,
and with IkappaBalpha and NF- kappaB's role in regulating inflammatory and
immune responses, is the normal development Of IkappaBalpha-deficient mice.
However, growth ceases 3 days after birth and death usually occurs at 7 to
10 days of age. An increased percentage of monocytes/macrophages was
detected in spleen cells taken from 5-, 7-, and 9-day-old pups. Death is
accompanied by severe widespread dermatitis and increased levels of TNF-
alpha mRNA in the skin.
Copyright © 1996, American Society for Microbiology
IkappaBalpha deficiency results in a sustained NF-kappaB response and severe widespread dermatitis in mice
Roche Institute of Molecular Biology, Roche Research Center, Nutley, New Jersey 07110, USA.
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