Control of nuclear factor-kB DNA-binding activity by inhibitory proteins containing ankyrin repeats

1993 ◽  
Vol 21 (4) ◽  
pp. 926-930 ◽  
Author(s):  
Ronald T. Hay
2001 ◽  
Vol 29 (6) ◽  
pp. 688-691 ◽  
Author(s):  
K. J. Campbell ◽  
N. R. Chapman ◽  
N. D. Perkins

The cellular response to DNA-damaging agents is partly mediated by DNA-binding transcription factors such as p53 and nuclear factor κB (NF-κB). Typically NF-κB activation is associated with resistance to apoptosis. Following stimulation with UV light however, NF-κB activation has been shown to be required for programmed cell death. To study this effect further and to determine the relationship between NF-κB and p53 function, we have examined the effect of UV light on U2OS cells. UV stimulation resulted in the activation of NF-κB DNA-binding and the induction of p53. Surprisingly, and in contrast with tumour necrosis factor α stimulation, this UV-induced NF-κB was transcriptionally inert. These observations suggest a model in which the NF-κB switch from an anti-apoptotic to a pro-apoptotic role within the cell results from modulation of its ability to stimulate gene expression, possibly as a result of the ability of p53 to sequester transcriptional co-activator proteins such as p300/CREB (cAMP-response-element-binding protein)-binding protein.


1997 ◽  
Vol 29 (1-2) ◽  
pp. 1172-1173
Author(s):  
K. Akioka ◽  
H. Nakajima ◽  
I. Fujiwara ◽  
N. Yoshimura ◽  
T. Matsuda ◽  
...  

1994 ◽  
Vol 14 (1) ◽  
pp. 128-137 ◽  
Author(s):  
V S Meier ◽  
B Groner

Expression of the beta-casein milk protein gene in the mammary epithelial cell line HC11 is primarily regulated at the transcriptional level. A 338-bp segment of promoter sequence 5' of the transcription start site is sufficient to confer inducibility by the lactogenic hormones insulin, glucocorticoid hormone, and prolactin. Positively and negatively acting promoter elements and specific DNA binding proteins have been identified. The binding of the mammary gland factor MGF to a site between -80 and -100 is indispensable for hormonal induction of transcription. Binding of MGF activity to DNA is greatly enhanced by the action of the lactogenic hormones. Repression of transcription in the uninduced state is mediated by a promoter element located adjacent to the MGF binding site at positions -110 to -150. This repressor element consists of two interacting protein binding sites. A nuclear factor that binds specifically to the proximal site between positions -110 and -120 has been characterized and found to be identical with the nuclear factor YY1 (delta, NF-E1). YY1 does not bind to the distal site. The simultaneous mutation in the proximal and the distal sites results in high, hormone-independent transcription. This finding suggests that YY1 plays a functional role in the repression and acts in conjunction with a second DNA binding protein. Comparison of YY1 DNA binding activity in uninduced and hormone-induced cells showed that relief of repression is not mediated by changes in the concentration or binding affinity of YY1. Infection of HC11 cells with a YY1-expressing recombinant retrovirus resulted in overexpression of YY1 but did not suppress hormonal induction. The addition of purified MGF decreased YY1 binding to its DNA recognition site in vitro. This finding indicates that MGF regulates the DNA binding activity of YY1 and thereby may cause the relief of transcriptional repression.


Blood ◽  
1997 ◽  
Vol 90 (7) ◽  
pp. 2690-2700 ◽  
Author(s):  
Sonja I. Gringhuis ◽  
Lou F.M.H. de Leij ◽  
Emmy W. Verschuren ◽  
Peter Borger ◽  
Edo Vellenga

Abstract In the present report, we studied the role of the stromal-derived cytokine interleukin-7 (IL-7) in the IL-2–gene regulation in activated T lymphocytes. Production of IL-2 requires the formation of transcription factors involved in the IL-2 –gene regulation. T-cell receptor (TCR)/CD3 engagement results in the activation of nuclear factor of activated T cells (NFAT), activator protein-1 (AP-1), and nuclear factor κB (NFκB), whereas the CD28 responsive complex (CD28RC) is activated in response to the CD28 signal. Costimulation of phytohemagglutinin/anti-CD28 activated T lymphocytes with IL-7 induces a fivefold enhanced IL-2–mRNA accumulation and a 2.5-fold enhanced protein secretion. The IL-2–gene transcription rate is increased 3.4-fold, indicating that the effect of IL-7 is in part mediated at the transcriptional level. The molecular mechanisms underlying the IL-7 effect involve the upregulation of the DNA binding activity of NFAT (60%) and AP-1 (120%), without affecting the activities of NFκB and CD28RC, which was confirmed by transfection assays. We also show that the IL-7–induced enhancement of the AP-1–DNA binding activity is not cyclosporin A-sensitive. Since AP-1 is part of the NFAT complex, we conclude that the IL-7–signaling pathway is involved in the activation of the fos and jun proteins of which AP-1 consists.


1994 ◽  
Vol 14 (1) ◽  
pp. 128-137
Author(s):  
V S Meier ◽  
B Groner

Expression of the beta-casein milk protein gene in the mammary epithelial cell line HC11 is primarily regulated at the transcriptional level. A 338-bp segment of promoter sequence 5' of the transcription start site is sufficient to confer inducibility by the lactogenic hormones insulin, glucocorticoid hormone, and prolactin. Positively and negatively acting promoter elements and specific DNA binding proteins have been identified. The binding of the mammary gland factor MGF to a site between -80 and -100 is indispensable for hormonal induction of transcription. Binding of MGF activity to DNA is greatly enhanced by the action of the lactogenic hormones. Repression of transcription in the uninduced state is mediated by a promoter element located adjacent to the MGF binding site at positions -110 to -150. This repressor element consists of two interacting protein binding sites. A nuclear factor that binds specifically to the proximal site between positions -110 and -120 has been characterized and found to be identical with the nuclear factor YY1 (delta, NF-E1). YY1 does not bind to the distal site. The simultaneous mutation in the proximal and the distal sites results in high, hormone-independent transcription. This finding suggests that YY1 plays a functional role in the repression and acts in conjunction with a second DNA binding protein. Comparison of YY1 DNA binding activity in uninduced and hormone-induced cells showed that relief of repression is not mediated by changes in the concentration or binding affinity of YY1. Infection of HC11 cells with a YY1-expressing recombinant retrovirus resulted in overexpression of YY1 but did not suppress hormonal induction. The addition of purified MGF decreased YY1 binding to its DNA recognition site in vitro. This finding indicates that MGF regulates the DNA binding activity of YY1 and thereby may cause the relief of transcriptional repression.


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