Epidermal growth factor receptor-mediated expression of NF-kappaB transcription factor in osteoblastic MC3T3-E1 cells cultured under a low-calcium environment.
We examined the effect of a low calcium environment on DNA-protein binding reaction activity of the transcription factor, NF-kappaB in osteoblastic MC3T3-E1 cells, using an electrophoretic mobility shift assay. Binding sites for the NF-kappaB sequence in DNA in nuclear protein in MC3T3-E1 cells are present. This DNA-protein binding reaction activity increased in MC3T3-E1 cells with EGF treatment, compared with those with no treatment. When MC3T3-E1 cells were placed in a low calcium environment, DNA-protein binding reaction activity seemed to decrease. This suggests that the phosphorylation of IkappaB is less active in a low calcium environment as compared with that in a normal calcium environment, because the activation of NF-kappaB is required for the dissociation of the cytoplasmic heterodimer after the phosphorylation of IkappaB. From these facts, it was suggested that gene transcription factor NF-kappaB is intimately associated with inhibitory bone formation in osteoblastic cells.
Matsumoto
A
A
Department of Dental Pharmacology, School of Dentistry, Hokkaido University, Sapporo, Japan.
Deyama
Y
Y
Deyama
A
A
Okitsu
M
M
Yoshimura
Y
Y
Suzuki
K
K
D000818:Animals; D002118:Calcium / Q000172:deficiency* / Q000494:pharmacology / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D016384:Consensus Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D066246:ErbB Receptors / Q000502:physiology*; D051379:Mice; D016328:NF-kappa B / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D009841:Oligonucleotides / Q000235:genetics / Q000494:pharmacology; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure
D004268:DNA-Binding Proteins; D016328:NF-kappa B; D009841:Oligonucleotides; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D002118:Calcium