scholarly journals Structure of Fission Yeast Transcription Factor Pho7 Bound to pho1 Promoter DNA and Effect of Pho7 Mutations on DNA Binding and Phosphate Homeostasis

2019 ◽  
Vol 39 (13) ◽  
Author(s):  
Angad Garg ◽  
Yehuda Goldgur ◽  
Ana M. Sanchez ◽  
Beate Schwer ◽  
Stewart Shuman

ABSTRACT Pho7 is the Schizosaccharomyces pombe fission yeast Zn2Cys6 transcriptional factor that drives a response to phosphate starvation in which phosphate acquisition genes are upregulated. Here we report a crystal structure at 1.6-Å resolution of the Pho7 DNA-binding domain (DBD) bound at its target site 2 in the pho1 promoter (5′-TCGGAAATTAAAAA). Comparison to the previously reported structure of Pho7 DBD in complex with its binding site in the tgp1 promoter (5′-TCGGACATTCAAAT) reveals shared determinants of target site specificity as well as variations in the protein-DNA interface that accommodate different promoter DNA sequences. Mutagenesis of Pho7 amino acids at the DNA interface identified nucleobase contacts at the periphery of the footprint that are essential for the induction of pho1 expression in response to phosphate starvation and for Pho7 binding to site 1 in the pho1 promoter.

mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Beate Schwer ◽  
Ana M. Sanchez ◽  
Angad Garg ◽  
Debashree Chatterjee ◽  
Stewart Shuman

ABSTRACT Fission yeast phosphate homeostasis entails transcriptional induction of genes encoding phosphate-mobilizing proteins under conditions of phosphate starvation. Transcription factor Pho7, a member of the Zn 2 Cys 6 family of fungal transcription regulators, is the central player in the starvation response. The DNA binding sites in the promoters of phosphate-responsive genes have not been defined, nor have any structure-function relationships been established for the Pho7 protein. Here we narrow this knowledge gap by (i) delineating an autonomous DNA-binding domain (DBD) within Pho7 that includes the Zn 2 Cys 6 module, (ii) deploying recombinant Pho7 DBD in DNase I footprinting and electrophoretic mobility shift assays (EMSAs) to map the Pho7 recognition sites in the promoters of the phosphate-regulated pho1 and tgp1 genes to a 12-nucleotide sequence motif [5′-TCG(G/C)(A/T)xxTTxAA], (iii) independently identifying the same motif as a Pho7 recognition element via in silico analysis of available genome-wide ChIP-seq data, (iv) affirming that mutations in the two Pho7 recognition sites in the pho1 promoter efface pho1 expression in vivo , and (v) establishing that the zinc-binding cysteines and a pair of conserved arginines in the DBD are essential for Pho7 activity in vivo . IMPORTANCE Fungi respond to phosphate starvation by inducing the transcription of a set of phosphate acquisition genes that comprise a phosphate regulon. Pho7, a member of the Zn 2 Cys 6 family of fungal transcription regulators, is the central player in the phosphate starvation response in fission yeast. The present study identifies a 12-nucleotide Pho7 DNA binding motif [5′-TCG(G/C)(A/T)xxTTxAA] in the promoters of phosphate-regulated genes, pinpoints DNA and protein features important for Pho7 binding to DNA, and correlates them with Pho7-dependent gene expression in vivo . The results highlight distinctive properties of Pho7 vis-a-vis other fungal zinc binuclear cluster transcription factors as well as the divergent cast of transcription factors deployed for phosphate homeostasis in fission yeast versus budding yeast.


Author(s):  
Ruby Sharma ◽  
Shanti P. Gangwar ◽  
Ajay K. Saxena

ERG3 (ETS-related gene) is a member of the ETS (erythroblast transformation-specific) family of transcription factors, which contain a highly conserved DNA-binding domain. The ETS family of transcription factors differ in their binding to promoter DNA sequences, and the mechanism of their DNA-sequence discrimination is little known. In the current study, crystals of the ETSi domain (the ETS domain of ERG3 containing a CID motif) in space group P41212 and of its complex with the E74 DNA sequence (DNA9) in space group C2221 were obtained and their structures were determined. Comparative structure analysis of the ETSi domain and its complex with DNA9 with previously determined structures of the ERGi domain (the ETS domain of ERG containing inhibitory motifs) in space group P65212 and of the ERGi–DNA12 complex in space group P41212 were performed. The ETSi domain is observed as a homodimer in solution as well as in the crystallographic asymmetric unit. Superposition of the structure of the ETSi domain on that of the ERGi domain showed a major conformational change at the C-terminal DNA-binding autoinhibitory (CID) motif, while minor changes are observed in the loop regions of the ETSi-domain structure. The ETSi–DNA9 complex in space group C2221 forms a structure that is quite similar to that of the ERG–DNA12 complex in space group P41212. Upon superposition of the complexes, major conformational changes are observed at the 5′ and 3′ ends of DNA9, while the conformation of the core GGA nucleotides was quite conserved. Comparison of the ETSi–DNA9 structure with known structures of ETS class 1 protein–DNA complexes shows the similarities and differences in the promoter DNA binding and specificity of the class 1 ETS proteins.


mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Begoña Monterroso ◽  
Silvia Zorrilla ◽  
Marta Sobrinos-Sanguino ◽  
Miguel Ángel Robles-Ramos ◽  
Carlos Alfonso ◽  
...  

ABSTRACTDivision ring formation at midcell is controlled by various mechanisms inEscherichia coli, one of them being the linkage between the chromosomal Ter macrodomain and the Z-ring mediated by MatP, a DNA binding protein that organizes this macrodomain and contributes to the prevention of premature chromosome segregation. Here we show that, during cell division, just before splitting the daughter cells, MatP seems to localize close to the cytoplasmic membrane, suggesting that this protein might interact with lipids. To test this hypothesis, we investigated MatP interaction with lipidsin vitro. We found that, when encapsulated inside vesicles and microdroplets generated by microfluidics, MatP accumulates at phospholipid bilayers and monolayers matching the lipid composition in theE. coliinner membrane. MatP binding to lipids was independently confirmed using lipid-coated microbeads and biolayer interferometry assays, which suggested that the recognition is mainly hydrophobic. Interaction of MatP with the lipid membranes also occurs in the presence of the DNA sequences specifically targeted by the protein, but there is no evidence of ternary membrane/protein/DNA complexes. We propose that the association of MatP with lipids may modulate its spatiotemporal localization and its recognition of other ligands.IMPORTANCEThe division of anE. colicell into two daughter cells with equal genomic information and similar size requires duplication and segregation of the chromosome and subsequent scission of the envelope by a protein ring, the Z-ring. MatP is a DNA binding protein that contributes both to the positioning of the Z-ring at midcell and the temporal control of nucleoid segregation. Our integratedin vivoandin vitroanalysis provides evidence that MatP can interact with lipid membranes reproducing the phospholipid mixture in theE. coliinner membrane, without concomitant recruitment of the short DNA sequences specifically targeted by MatP. This observation strongly suggests that the membrane may play a role in the regulation of the function and localization of MatP, which could be relevant for the coordination of the two fundamental processes in which this protein participates, nucleoid segregation and cell division.


1996 ◽  
Vol 16 (11) ◽  
pp. 6096-6102 ◽  
Author(s):  
K Hellauer ◽  
M H Rochon ◽  
B Turcotte

The Gal4, Put3, and Ppr1 yeast zinc cluster proteins bind as homodimers to DNA sequences composed of palindromic CGG triplets. Spacing between the triplets specifies the target site for a given zinc cluster protein. In addition, Hap1p, another zinc cluster protein, also recognizes CGG triplets but only when oriented as a direct repeat. Unexpectedly, our results show that Leu3p, another member of this family, also recognizes CGG triplets but oriented in opposite directions and spaced by 4 nucleotides (an everted repeat or inverted palindrome: CCG-N4-CGG). This constitutes a novel DNA motif for zinc cluster proteins. Moreover, the presence of this motif was shown to be essential for in vivo activation by Leu3p of a minimal reporter containing one copy of a target site for this activator. We also provide evidence that another member of this family, Pdr3p, binds to an everted repeat spaced by 0 nucleotides (CCGCGG). Thus, our results show that three CGG motifs are used by members of the zinc cluster family: palindromes, direct repeats, and everted repeats.


2015 ◽  
Vol 197 (14) ◽  
pp. 2383-2391 ◽  
Author(s):  
Semen A. Leyn ◽  
Irina A. Rodionova ◽  
Xiaoqing Li ◽  
Dmitry A. Rodionov

ABSTRACTAutotrophic microorganisms are able to utilize carbon dioxide as their only carbon source, or, alternatively, many of them can grow heterotrophically on organics. Different variants of autotrophic pathways have been identified in various lineages of the phylumCrenarchaeota. Aerobic members of the orderSulfolobalesutilize the hydroxypropionate-hydroxybutyrate cycle (HHC) to fix inorganic carbon, whereas anaerobicThermoprotealesuse the dicarboxylate-hydroxybutyrate cycle (DHC). Knowledge of transcriptional regulation of autotrophic pathways inArchaeais limited. We applied a comparative genomics approach to predict novel autotrophic regulons in theCrenarchaeota. We report identification of two novel DNA motifs associated with the autotrophic pathway genes in theSulfolobales(HHC box) andThermoproteales(DHC box). Based on genome context evidence, the HHC box regulon was attributed to a novel transcription factor from the TrmB family named HhcR. Orthologs of HhcR are present in allSulfolobalesgenomes but were not found in other lineages. A predicted HHC box regulatory motif was confirmed byin vitrobinding assays with the recombinant HhcR protein fromMetallosphaera yellowstonensis. For the DHC box regulon, we assigned a different potential regulator, named DhcR, which is restricted to the orderThermoproteales. DhcR inThermoproteus neutrophilus(Tneu_0751) was previously identified as a DNA-binding protein with high affinity for the promoter regions of two autotrophic operons. The global HhcR and DhcR regulons reconstructed by comparative genomics were reconciled with available omics data inMetallosphaeraandThermoproteusspp. The identified regulons constitute two novel mechanisms for transcriptional control of autotrophic pathways in theCrenarchaeota.IMPORTANCELittle is known about transcriptional regulation of carbon dioxide fixation pathways inArchaea. We previously applied the comparative genomics approach for reconstruction of DtxR family regulons in diverse lineages ofArchaea. Here, we utilize similar computational approaches to identify novel regulatory motifs for genes that are autotrophically induced in microorganisms from two lineages ofCrenarchaeotaand to reconstruct the respective regulons. The predicted novel regulons in archaeal genomes control the majority of autotrophic pathway genes and also other carbon and energy metabolism genes. The HhcR regulon was experimentally validated by DNA-binding assays inMetallosphaeraspp. Novel regulons described for the first time in this work provide a basis for understanding the mechanisms of transcriptional regulation of autotrophic pathways inArchaea.


2019 ◽  
Vol 201 (17) ◽  
Author(s):  
Dragutin J. Savic ◽  
Scott V. Nguyen ◽  
Kimberly McCullor ◽  
W. Michael McShan

ABSTRACTA large-scale genomic inversion encompassing 0.79 Mb of the 1.816-Mb-longStreptococcus pyogenesserotype M49 strain NZ131 chromosome spontaneously occurs in a minor subpopulation of cells, and in this report genetic selection was used to obtain a stable lineage with this chromosomal rearrangement. This inversion, which drastically displaces theorisite relative to the terminus, changes the relative length of the replication arms so that one replichore is approximately 0.41 Mb while the other is about 1.40 Mb in length. Genomic reversion to the original chromosome constellation is not observed in PCR-monitored analyses after 180 generations of growth in rich medium. Compared to the parental strain, the inversion surprisingly demonstrates a nearly identical growth pattern in the first phase of the exponential phase, but differences do occur when resources in the medium become limited. When cultured separately in rich medium during prolonged stationary phase or in an experimental acute infection animal model (Galleria mellonella), the parental strain and the invertant have equivalent survival rates. However, when they are coincubated together, bothin vitroandin vivo, the survival of the invertant declines relative to the level for the parental strain. The accompanying aspect of the study suggests that inversions taking place nearoriCalways happen to secure the linkage oforiCto DNA sequences responsible for chromosome partition. The biological relevance of large-scale inversions is also discussed.IMPORTANCEBased on our previous work, we created to our knowledge the largest asymmetric inversion, covering 43.5% of theS. pyogenesgenome. In spite of a drastic replacement of origin of replication and the unbalanced size of replichores (1.4 Mb versus 0.41 Mb), the invertant, when not challenged with its progenitor, showed impressive vitality for growthin vitroand in pathogenesis assays. The mutant supports the existing idea that slightly deleterious mutations can provide the setting for secondary adaptive changes. Furthermore, comparative analysis of the mutant with previously published data strongly indicates that even large genomic rearrangements survive provided that the integrity of theoriCand the chromosome partition cluster is preserved.


1993 ◽  
Vol 13 (11) ◽  
pp. 6810-6818 ◽  
Author(s):  
X Y Zhang ◽  
N Jabrane-Ferrat ◽  
C K Asiedu ◽  
S Samac ◽  
B M Peterlin ◽  
...  

A mammalian protein called RFX or NF-X binds to the X box (or X1 box) in the promoters of a number of major histocompatibility (MHC) class II genes. In this study, RFX was shown to have the same DNA-binding specificity as methylated DNA-binding protein (MDBP), and its own cDNA was found to contain a binding site for MDBP in the leader region. MDBP is a ubiquitous mammalian protein that binds to certain DNA sequences preferentially when they are CpG methylated and to other related sequences, like the X box, irrespective of DNA methylation. MDBP from HeLa and Raji cells formed DNA-protein complexes with X-box oligonucleotides that coelectrophoresed with those containing standard MDBP sites. Furthermore, MDBP and X-box oligonucleotides cross-competed for the formation of these DNA-protein complexes. DNA-protein complexes obtained with MDBP sites displayed the same partial supershifting with an antiserum directed to the N terminus of RFX seen for complexes containing an X-box oligonucleotide. Also, the in vitro-transcribed-translated product of a recombinant RFX cDNA bound specifically to MDBP ligands and displayed the DNA methylation-dependent binding of MDBP. RFX therefore contains MDBP activity and thereby also EF-C, EP, and MIF activities that are indistinguishable from MDBP and that bind to methylation-independent sites in the transcriptional enhancers of polyomavirus and hepatitis B virus and to an intron of c-myc.


2016 ◽  
Vol 198 (10) ◽  
pp. 1543-1552 ◽  
Author(s):  
Yanping Yin ◽  
Youyun Yang ◽  
Xuwu Xiang ◽  
Qian Wang ◽  
Zhang-Nv Yang ◽  
...  

ABSTRACTIt is well established that the RpoN-RpoS sigma factor (σ54-σS) cascade plays an essential role in differential gene expression during the enzootic cycle ofBorrelia burgdorferi, the causative agent of Lyme disease. The RpoN-RpoS pathway is activated by the response regulator/σ54-dependent activator (also called bacterial enhancer-binding protein [bEBP]) Rrp2. One unique feature of Rrp2 is that this activator is essential for cell replication, whereas RpoN-RpoS is dispensable for bacterial growth. How Rrp2 controls cell replication, a function that is independent of RpoN-RpoS, remains to be elucidated. In this study, by generating a series of conditionalrrp2mutant strains, we demonstrated that the N-terminal receiver domain of Rrp2 is required for spirochetal growth. Furthermore, a D52A point mutation at the phosphorylation site within the N terminus of Rrp2 abolished cell replication. Mutation of the ATPase motif within the central domain of Rrp2 did not affect spirochetal replication, indicating that phosphorylation-dependent ATPase activity of Rrp2 for σ54activation is not required for cell growth. However, deletion of the C-terminal domain or a 16-amino-acid truncation of the helix-turn-helix (HTH) DNA-binding motif within the C-terminal domain of Rrp2 abolished spirochetal replication. It was shown that constitutive expression ofrpoSis deleterious to borrelial growth. We showed that the essential nature of Rrp2 is not due to an effect onrpoS. These data suggest that phosphorylation-dependent oligomerization and DNA binding of Rrp2 likely function as a repressor, independently of the activation of σ54, controlling an essential step of cell replication inB. burgdorferi.IMPORTANCEBacterial enhancer-binding proteins (bEBPs) are a unique group of transcriptional activators specifically required for σ54-dependent gene transcription. This work demonstrates that theB. burgdorferibEBP, Rrp2, has an additional function that is independent of σ54, that of its essentiality for spirochetal growth, and such a function is dependent on its N-terminal signal domain and C-terminal DNA-binding domain. These findings expand our knowledge on bEBP and provide a foundation to further study the underlying mechanism of this new function of bEBP.


2003 ◽  
Vol 15 (8) ◽  
pp. 1771-1780 ◽  
Author(s):  
Akio Miyao ◽  
Katsuyuki Tanaka ◽  
Kazumasa Murata ◽  
Hiromichi Sawaki ◽  
Shin Takeda ◽  
...  
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