Interaction of the CNC-bZIP factor TCF11/LCR-F1/Nrf1 with MafG: binding-site selection and regulation of transcription
Citation:
Johnsen, O. and Murphy, P., Prydz, H. and Kolsto, A-B., Interaction of the CNC-bZIP factor TCF11/LCR-F1/Nrf1 with MafG: binding-site selection and regulation of transcription, Nucleic Acids Research, 26, 2, 1998, 512, 520Download Item:
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Abstract:
We have previously shown that the widely expressed
human transcription factor TCF11/LCR-F1/Nrf1 interacts
with small Maf proteins and binds to a subclass of
AP1-sites. Such sites are required for b-globin 54 DNase
I hypersensitive site 2 enhancer activity, erythroid
porphobilinogen deaminase inducibility, hemin
responsiveness by heme-oxygenase 1 and expression
of the gene NAD(P)H:quinone oxidoreductase1. Here
we report the optimal DNA-binding sequences for
TCF11/LCR-F1/Nrf1 alone and as a heterodimer with
MafG, identified by using binding-site selection. The
heterodimer recognises a 54-TGCTgaGTCAT-34 bindingsite
that is identical to the established NF-E2-site, the
antioxidant response element and the heme-responsive
element while the binding specificity of the homomer is
less stringent. To investigate the activity of TCF11
through this selected site, both alone and in the
presence of MafG, we have used a transient
transfection assay. TCF11 alone activates transcription
while MafG alone acts as a repressor. When coexpressed,
MafG interferes with TCF11 transactivation
in a dose dependent manner. This indicates that MafG
protein, which heterodimerises efficiently with TCF11 in
vitro (the heterodimer having a higher affinity for DNA
than TCF11 alone), does not co-operate with TCF11 in
transactivating transcription. We propose that since
both these factors are widely expressed, they may act
together to contribute to the negative regulation of this
specific target site. Efficient positive regulation by
TCF11 may require alternative partners with perhaps
more restricted expression patterns.
Author's Homepage:
http://people.tcd.ie/pmurphy3Description:
PUBLISHEDJohnsen & Murphy - joint first authors PMID: 9421508
Author: MURPHY, PAULA
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Nucleic Acids Research26
2
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