Crystal Structure of the DNA-binding Domain of the LysR-type Transcriptional Regulator CbnR in Complex with a DNA Fragment of the Recognition-binding Site

ABSTRACT Pot1 is a single-stranded-DNA-binding protein that recognizes telomeric G-strand DNA. It is essential for telomere capping in Saccharomyces pombe and regulates telomere length in humans. Human Pot1 also interacts with proteins that bind the duplex region of the telomeric tract. Thus, like Cdc13 from S. cerevisiae, Pot 1 may have multiple roles at the telomere. We show here that endogenous chicken Pot1 (cPot1) is present at telomeres during periods of the cell cycle when t loops are thought to be present. Since cPot1 can bind internal loops and directly adjacent DNA-binding sites, it is likely to fully coat and protect both G-strand overhangs and the displaced G strand of a t loop. The minimum binding site of cPot1 is double that of the S. pombe DNA-binding domain. Although cPot can self associate, dimerization is not required for DNA binding and hence does not explain the binding-site duplication. Instead, the DNA-binding domain appears to be extended to contain a second binding motif in addition to the conserved oligonucleotide-oligosaccharide (OB) fold present in other G-strand-binding proteins. This second motif could be another OB fold. Although dimerization is inefficient in vitro, it may be regulated in vivo and could promote association with other telomere proteins and/or telomere compaction.

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Dissection of a carboxy-terminal region of the yeast regulatory protein RAP1 with effects on both transcriptional activation and silencing

Molecular and Cellular Biology ◽

10.1128/mcb.12.3.1209-1217.1992 ◽

1992 ◽

Vol 12 (3) ◽

pp. 1209-1217

Author(s):

C F Hardy ◽

D Balderes ◽

D Shore

Keyword(s):

Dna Binding ◽

Binding Site ◽

Transcriptional Activation ◽

Binding Sites ◽

Binding Protein ◽

Binding Domain ◽

Dominant Negative Effect ◽

Dna Binding Domain ◽

Wild Type ◽

Carboxy Terminal

RAP1 is an essential sequence-specific DNA-binding protein in Saccharomyces cerevisiae whose binding sites are found in a large number of promoters, where they function as upstream activation sites, and at the silencer elements of the HMR and HML mating-type loci, where they are important for repression. We have examined the involvement of specific regions of the RAP1 protein in both repression and activation of transcription by studying the properties of a series of hybrid proteins containing RAP1 sequences fused to the DNA-binding domain of the yeast protein GAL4 (amino acids 1 to 147). GAL4 DNA-binding domain/RAP1 hybrids containing only the carboxy-terminal third of the RAP1 protein (which lacks the RAP1 DNA-binding domain) function as transcriptional activators of a reporter gene containing upstream GAL4 binding sites. Expression of some hybrids from the strong ADH1 promoter on multicopy plasmids has a dominant negative effect on silencers, leading to either partial or complete derepression of normally silenced genes. The GAL4/RAP1 hybrids have different effects on wild-type and several mutated but functional silencers. Silencers lacking either an autonomously replicating sequence consensus element or the RAP1 binding site are strongly derepressed, whereas the wild-type silencer or a silencer containing a deletion of the binding site for another silencer-binding protein, ABF1, are only weakly affected by hybrid expression. By examining a series of GAL4 DNA-binding domain/RAP1 hybrids, we have mapped the transcriptional activation and derepression functions to specific parts of the RAP1 carboxy terminus.(ABSTRACT TRUNCATED AT 250 WORDS)

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Crystal structure of the DNA-binding domain of BldD, a central regulator of aerial mycelium formation in Streptomyces coelicolor A3(2)

Molecular Microbiology ◽

10.1111/j.1365-2958.2006.05176.x ◽

2006 ◽

Vol 60 (5) ◽

pp. 1179-1193 ◽

Cited By ~ 17

Author(s):

In-Kwon Kim ◽

Chang-Jin Lee ◽

Min-Kyu Kim ◽

Jeong-Mok Kim ◽

Ji-Hye Kim ◽

...

Keyword(s):

Crystal Structure ◽

Dna Binding ◽

Streptomyces Coelicolor ◽

Aerial Mycelium ◽

Binding Domain ◽

Dna Binding Domain

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Crystal structure of the trithorax group protein ASH2L reveals a forkhead-like DNA binding domain

Nature Structural & Molecular Biology ◽

10.1038/nsmb.2093 ◽

2011 ◽

Vol 18 (7) ◽

pp. 857-859 ◽

Cited By ~ 27

Author(s):

Sabina Sarvan ◽

Vanja Avdic ◽

Véronique Tremblay ◽

Chandra-Prakash Chaturvedi ◽

Pamela Zhang ◽

...

Keyword(s):

Crystal Structure ◽

Dna Binding ◽

Binding Domain ◽

Dna Binding Domain ◽

Trithorax Group ◽

Group Protein

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Dissection of a carboxy-terminal region of the yeast regulatory protein RAP1 with effects on both transcriptional activation and silencing.

Molecular and Cellular Biology ◽

10.1128/mcb.12.3.1209 ◽

1992 ◽

Vol 12 (3) ◽

pp. 1209-1217 ◽

Cited By ~ 49

Author(s):

C F Hardy ◽

D Balderes ◽

D Shore

Keyword(s):

Dna Binding ◽

Binding Site ◽

Transcriptional Activation ◽

Binding Sites ◽

Binding Protein ◽

Binding Domain ◽

Dominant Negative Effect ◽

Dna Binding Domain ◽

Wild Type ◽

Carboxy Terminal

RAP1 is an essential sequence-specific DNA-binding protein in Saccharomyces cerevisiae whose binding sites are found in a large number of promoters, where they function as upstream activation sites, and at the silencer elements of the HMR and HML mating-type loci, where they are important for repression. We have examined the involvement of specific regions of the RAP1 protein in both repression and activation of transcription by studying the properties of a series of hybrid proteins containing RAP1 sequences fused to the DNA-binding domain of the yeast protein GAL4 (amino acids 1 to 147). GAL4 DNA-binding domain/RAP1 hybrids containing only the carboxy-terminal third of the RAP1 protein (which lacks the RAP1 DNA-binding domain) function as transcriptional activators of a reporter gene containing upstream GAL4 binding sites. Expression of some hybrids from the strong ADH1 promoter on multicopy plasmids has a dominant negative effect on silencers, leading to either partial or complete derepression of normally silenced genes. The GAL4/RAP1 hybrids have different effects on wild-type and several mutated but functional silencers. Silencers lacking either an autonomously replicating sequence consensus element or the RAP1 binding site are strongly derepressed, whereas the wild-type silencer or a silencer containing a deletion of the binding site for another silencer-binding protein, ABF1, are only weakly affected by hybrid expression. By examining a series of GAL4 DNA-binding domain/RAP1 hybrids, we have mapped the transcriptional activation and derepression functions to specific parts of the RAP1 carboxy terminus.(ABSTRACT TRUNCATED AT 250 WORDS)

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