scholarly journals LIM Protein KyoT2 Negatively Regulates Transcription by Association with the RBP-J DNA-Binding Protein

1998 ◽  
Vol 18 (1) ◽  
pp. 644-654 ◽  
Author(s):  
Yoshihito Taniguchi ◽  
Takahisa Furukawa ◽  
Tin Tun ◽  
Hua Han ◽  
Tasuku Honjo
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Negative Regulator ◽  
Nuclear Antigen ◽  
Differential Splicing ◽  
Barr Virus ◽  
Lim Domains ◽  
C Terminus

ABSTRACT The RBP-J/Su(H) DNA-binding protein plays a key role in transcriptional regulation by targeting Epstein-Barr virus nuclear antigen 2 (EBNA2) and the intracellular portions of Notch receptors to specific promoters. Using the yeast two-hybrid system, we isolated a LIM-only protein, KyoT, which physically interacts with RBP-J. Differential splicing gave rise to two transcripts of theKyoT gene, KyoT1 and KyoT2, that encoded proteins with four and two LIM domains, respectively. With differential splicing resulting in deletion of an exon, KyoT2 lacked two LIM domains from the C terminus and had a frameshift in the last exon, creating the RBP-J-binding region in the C terminus. KyoT1 had a negligible level of interaction with RBP-J. Strong expression of KyoT mRNAs was detected in skeletal muscle and lung, with a predominance of KyoT1 mRNA. When expressed in F9 embryonal carcinoma cells, KyoT1 and KyoT2 were localized in the cytoplasm and the nucleus, respectively. The binding site of KyoT2 on RBP-J overlaps those of EBNA2 and Notch1 but is distinct from that of Hairless, the negative regulator of RBP-J-mediated transcription in Drosophila. KyoT2 but not KyoT1 repressed the RBP-J-mediated transcriptional activation by EBNA2 and Notch1 by competing with them for binding to RBP-J and by dislocating RBP-J from DNA. KyoT2 is a novel negative regulatory molecule for RBP-J-mediated transcription in mammalian systems.

scholarly journals Epstein–Barr virus nuclear antigen 1 is a DNA-binding protein with strong RNA-binding activity

2004 ◽  
Vol 85 (10) ◽  
pp. 2755-2765 ◽  
Author(s):  
Chih-Chung Lu ◽  
Chia-Wei Wu ◽  
Shin C. Chang ◽  
Tzu-Yi Chen ◽  
Chwan-Ren Hu ◽  
...  
Keyword(s):  
Dna Binding ◽  
Epstein Barr Virus ◽  
Rna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Binding Activity ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Infected Cells ◽  
Epstein Barr

Epstein–Barr virus (EBV) nuclear antigen 1 (EBNA-1) plays key roles in both the regulation of gene expression and the replication of the EBV genome in latently infected cells. To characterize the RNA-binding activity of EBNA-1, it was demonstrated that EBNA-1 binds efficiently to RNA homopolymers that are composed of poly(G) and weakly to those composed of poly(U). All three RGG boxes of EBNA-1 contributed additively to poly(G)-binding activity and could mediate RNA binding when attached to a heterologous protein in an RNA gel mobility-shift assay. In vitro-transcribed EBV and non-EBV RNA probes revealed that EBNA-1 bound to most RNAs examined and the affinity increased as the content of G and U increased, as demonstrated in competition assays. Among these probes, the 5′ non-coding region (NCR) (nt 131–278) of hepatitis C virus RNA appeared to be the strongest competitor for EBNA-1 binding to the EBV-encoded small nuclear RNA 1 (EBER1) probe, whereas a mutant 5′ NCR RNA with partially disrupted secondary structure was a weak competitor. Furthermore, the interaction of endogenous EBNA-1 and EBER1 in EBV-infected cells was demonstrated by a ribonucleoprotein immunoprecipitation assay. These results revealed that EBNA-1 is a DNA-binding protein with strong binding activity to a relatively broad spectrum of RNA and suggested an additional biological impact of EBNA-1 through its ability to bind to RNA.

scholarly journals The E-box DNA binding protein Sgc1p suppresses thegcr2mutation, which is involved in transcriptional activation of glycolytic genes inSaccharomyces cerevisiae

FEBS Letters ◽  
1999 ◽  
Vol 463 (3) ◽  
pp. 307-311 ◽  
Author(s):  
Takashi Sato ◽  
M.Cecilia Lopez ◽  
Shigemi Sugioka ◽  
Yoshifumi Jigami ◽  
Henry V. Baker ◽  
...  
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
E Box

scholarly journals Complex formation between p53 and replication protein A inhibits the sequence-specific DNA binding of p53 and is regulated by single-stranded DNA.

1997 ◽  
Vol 17 (4) ◽  
pp. 2194-2201 ◽  
Author(s):  
S D Miller ◽  
K Moses ◽  
L Jayaraman ◽  
C Prives
Keyword(s):  
Dna Binding ◽  
Complex Formation ◽  
Binding Protein ◽  
Protein A ◽  
Replication Protein A ◽  
Dna Binding Protein ◽  
Replication Protein ◽  
Single Stranded Dna ◽  
C Terminus ◽  
P53 Response

Human replication protein A (RP-A) (also known as human single-stranded DNA binding protein, or HSSB) is a multisubunit complex involved in both DNA replication and repair. Potentially important to both these functions, it is also capable of complex formation with the tumor suppressor protein p53. Here we show that although p53 is unable to prevent RP-A from associating with a range of single-stranded DNAs in solution, RP-A is able to strongly inhibit p53 from functioning as a sequence-specific DNA binding protein when the two proteins are complexed. This inhibition, in turn, can be regulated by the presence of various lengths of single-stranded DNAs, as RP-A, when bound to these single-stranded DNAs, is unable to interact with p53. Interestingly, the lengths of single-stranded DNA capable of relieving complex formation between the two proteins represent forms that might be introduced through repair and replicative events. Increasing p53 concentrations can also overcome the inhibition by steady-state levels of RP-A, potentially mimicking cellular points of balance. Finally, it has been shown previously that p53 can itself be stimulated for site-specific DNA binding when complexed through the C terminus with short single strands of DNA, and here we show that p53 stays bound to these short strands even after binding a physiologically relevant site. These results identify a potential dual role for single-stranded DNA in the regulation of DNA binding by p53 and give insights into the p53 response to DNA damage.

Early Nuclear Antigen as DNA-Binding Protein in Cytomegalovirus-Infected Cells

Intervirology ◽  
1980 ◽  
Vol 13 (6) ◽  
pp. 352-356 ◽  
Author(s):  
Lajos Gergely ◽  
Judit Czeglédy ◽  
Lajos Váczi
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Nuclear Antigen ◽  
Infected Cells

scholarly journals Isolation and analysis of the yeast TEA1 gene, which encodes a zinc cluster Ty enhancer-binding protein.

1996 ◽  
Vol 16 (1) ◽  
pp. 347-358 ◽  
Author(s):  
W M Gray ◽  
J S Fassler
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Binding Proteins ◽  
Binding Protein ◽  
Dna Binding Proteins ◽  
Yeast Cells ◽  
Regulatory Sequences ◽  
Zinc Cluster ◽  
Modest Contribution ◽  
C Terminus

A genetic screen for mutants that affect the activity of internal regulatory sequences of Ty retrotransposons led to the identification of a new gene encoding a DNA-binding protein that interacts with the downstream enhancer-like region of Ty1 elements. The TEA1 (Ty enhancer activator) gene sequence predicts a protein of 86.9 kDa whose N terminus contains a zinc cluster and dimerization motif typical of the Gal4-type family of DNA-binding proteins. The C terminus encodes an acidic domain with a net negative charge of -10 and the ability to mediate transcriptional activation. Like other zinc cluster proteins, purified Tea1 was found to bind to a partially palindromic CGGNxCCG repeat motif located in the Ty1 enhancer region. The Ty1 Tea1 binding site has a spacing of 10 and is located near binding sites for the DNA-binding proteins Rap1 and Mcm1. Analysis of the phenotype of tea1 deletion mutants confirmed that the TEA1 gene is required for activation from the internal Ty1 enhancer characterized in this study and makes a modest contribution to normal Ty1 levels in the cell. Hence, Tea1, like Rap1, is a member of a small family of downstream activators in Saccharomyces cerevisiae. Further analysis of the Tea1 protein and its interactions may provide insight into the mechanism of downstream activation in yeast cells.

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