IkappaBalpha deficiency results in a sustained NF-kappaB response and severe widespread dermatitis in mice.
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.
Klement
J F
JF
Roche Institute of Molecular Biology, Roche Research Center, Nutley, New Jersey 07110, USA.
Rice
N R
NR
Car
B D
BD
Abbondanzo
S J
SJ
Powers
G D
GD
Bhatt
P H
PH
Chen
C H
CH
Rosen
C A
CA
Stewart
C L
CL
D016475:3T3 Cells; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003001:Cloning, Molecular; D003513:Cycloheximide / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D003872:Dermatitis / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D004622:Embryo, Mammalian; D015870:Gene Expression; D006580:Genetic Carrier Screening; D005838:Genotype; D006720:Homozygote; D020672:I-kappa B Proteins; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008099:Liver / Q000378:metabolism / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D020569:Proto-Oncogene Proteins c-rel; D012333:RNA, Messenger / Q000032:analysis; D017384:Sequence Deletion; D012867:Skin / Q000378:metabolism / Q000473:pathology; D013154:Spleen / Q000378:metabolism / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000494:pharmacology
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D020569:Proto-Oncogene Proteins c-rel; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D003513:Cycloheximide