scholarly journals Mutational Analysis of AREA, a Transcriptional Activator Mediating Nitrogen Metabolite Repression in Aspergillus nidulans and a Member of the “Streetwise” GATA Family of Transcription Factors

1998 ◽  
Vol 62 (3) ◽  
pp. 586-596 ◽  
Author(s):  
Richard A. Wilson ◽  
Herbert N. Arst
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Dna Binding ◽  
Aspergillus Nidulans ◽  
Transcriptional Activator ◽  
Structural Genes ◽  
Gata Factor ◽  
Mutational Change ◽  
Nitrogen Metabolite Repression ◽  
Gata Family

SUMMARY The transcriptional activator AREA is a member of the GATA family of transcription factors and mediates nitrogen metabolite repression in the fungus Aspergillus nidulans. The nutritional versatility of A. nidulans and its amenability to classical and reverse genetic manipulations make the AREA DNA binding domain (DBD) a useful model for analyzing GATA family DBDs, particularly as structures of two AREA-DNA complexes have been determined. The 109 extant mutant forms of the AREA DBD surveyed here constitute one of the highest totals of eukaryotic transcription factor DBD mutants, are discussed in light of the roles of individual residues, and are compared to corresponding mutant sequence changes in other fungal GATA factor DBDs. Other topics include delineation of the DBD using both homology and mutational truncation, use of frameshift reversion to detect regions of tolerance to mutational change, the finding that duplication of the DBD can apparently enhance AREA function, and use of the AREA system to analyze a vertebrate GATA factor DBD. Some major points to emerge from work on the AREA DBD are (i) tolerance to sequence change (with retention of function) is surprisingly great, (ii) mutational changes in a transcription factor can have widely differing, even opposing, effects on expression of different structural genes so that monitoring expression of one or even several structural genes can be insufficient and possibly misleading, and (iii) a mutational change altering local hydrophobic packing and DNA binding target specificity can markedly influence the behavior of mutational changes elsewhere in the DBD.

scholarly journals The MSN1 and NHP6A Genes Suppress SWI6 Defects in Saccharomyces cerevisiae

Genetics ◽  
1999 ◽  
Vol 151 (1) ◽  
pp. 45-55
Author(s):  
Julia Sidorova ◽  
Linda Breeden
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Dna Binding ◽  
Gene Transcription ◽  
Chromatin Structure ◽  
Transcriptional Activator ◽  
Temperature Sensitive ◽  
Gene Products ◽  
Protein Association

Abstract Ankyrin (ANK) repeats were first found in the Swi6 transcription factor of Saccharomyces cerevisiae and since then were identified in many proteins of eukaryotes and prokaryotes. These repeats are thought to serve as protein association domains. In Swi6, ANK repeats affect DNA binding of both the Swi4/Swi6 and Mbp1/Swi6 complexes. We have previously described generation of random mutations within the ANK repeats of Swi6 that render the protein temperature sensitive in its ability to activate HO transcription. Two of these SWI6 mutants were used in a screen for high copy suppressors of this phenotype. We found that MSN1, which encodes a transcriptional activator, and NHP6A, which encodes an HMG-like protein, are able to suppress defective Swi6 function. Both of these gene products are involved in HO transcription, and Nhp6A may also be involved in CLN1 transcription. Moreover, because overexpression of NHP6A can suppress caffeine sensitivity of one of the SWI6 ANK mutants, swi6-405, other SWI6-dependent genes may also be affected by Nhp6A. We hypothesize that Nhp6A and Msn1 modulate Swi6-dependent gene transcription indirectly, through effects on chromatin structure or other transcription factors, because we have not been able to demonstrate that either Msn1 or Nhp6A interact with the Swi4/Swi6 complex.

scholarly journals HbxB Is a Key Regulator for Stress Response and β-Glucan Biogenesis in Aspergillus nidulans

2021 ◽  
Vol 9 (1) ◽  
pp. 144
Author(s):  
Sung-Hun Son ◽  
Mi-Kyung Lee ◽  
Ye-Eun Son ◽  
Hee-Soo Park
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Aspergillus Nidulans ◽  
Deletion Mutant ◽  
Phenotypic Analysis ◽  
Spore Viability ◽  
Fungal Development ◽  
Expression Of Genes ◽  
Trehalose Biosynthesis

Homeobox transcription factors are conserved in eukaryotes and act as multi-functional transcription factors in filamentous fungi. Previously, it was demonstrated that HbxB governs fungal development and spore viability in Aspergillus nidulans. Here, the role of HbxB in A. nidulans was further characterized. RNA-sequencing revealed that HbxB affects the transcriptomic levels of genes associated with trehalose biosynthesis and response to thermal, oxidative, and radiation stresses in asexual spores called conidia. A phenotypic analysis found that hbxB deletion mutant conidia were more sensitive to ultraviolet stress. The loss of hbxB increased the mRNA expression of genes associated with β-glucan degradation and decreased the amount of β-glucan in conidia. In addition, hbxB deletion affected the expression of the sterigmatocystin gene cluster and the amount of sterigmatocystin. Overall, these results indicated that HbxB is a key transcription factor regulating trehalose biosynthesis, stress tolerance, β-glucan degradation, and sterigmatocystin production in A.nidulans conidia.

scholarly journals DNA-binding specificity of GATA family transcription factors.

1993 ◽  
Vol 13 (7) ◽  
pp. 3999-4010 ◽  
Author(s):  
M Merika ◽  
S H Orkin
Keyword(s):  
Transcription Factors ◽  
Dna Binding ◽  
Mammalian Cells ◽  
Chimeric Protein ◽  
Binding Specificity ◽  
Mobility Shift ◽  
Binding Domains ◽  
Dna Binding Specificity ◽  
Mobility Shift Assay ◽  
Gata Family

GATA-binding proteins constitute a family of transcription factors that recognize a target site conforming to the consensus WGATAR (W = A or T and R = A or G). Here we have used the method of polymerase chain reaction-mediated random site selection to assess in an unbiased manner the DNA-binding specificity of GATA proteins. Contrary to our expectations, we show that GATA proteins bind a variety of motifs that deviate from the previously assigned consensus. Many of the nonconsensus sequences bind protein with high affinity, equivalent to that of conventional GATA motifs. By using the selected sequences as probes in the electrophoretic mobility shift assay, we demonstrate overlapping, but distinct, sequence preferences for GATA family members, specified by their respective DNA-binding domains. Furthermore, we provide additional evidence for interaction of amino and carboxy fingers of GATA-1 in defining its binding site. By performing cotransfection experiments, we also show that transactivation parallels DNA binding. A chimeric protein containing the finger domain of areA and the activation domains of GATA-1 is capable of activating transcription in mammalian cells through GATA motifs. Our findings suggest a mechanism by which GATA proteins might selectively regulate gene expression in cells in which they are coexpressed.

Dimeric transcription factor families: it takes two to tango but who decides on partners and the venue?

1992 ◽  
Vol 103 (1) ◽  
pp. 9-14 ◽  
Author(s):  
K.A. Lee
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Dna Binding ◽  
Experimental Evidence ◽  
Cdna Cloning ◽  
Transcriptional Activation ◽  
Effector Functions ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Dna Elements

Dimeric transcription factors that bind to DNA are often grouped into families on the basis of dimerization and DNA-binding specificities. cDNA cloning studies have established that members of the same family have structurally related dimerisation and DNA-binding domains but diverge in other regions that are important for transcriptional activation. These features lead to the straightforward suggestion that although all members of a family bind to similar DNA elements, individual members exhibit distinct transcriptional effector functions. This simple view is now supported by experimental evidence from those systems that have proved amenable to study. There are however some largely unaddressed questions that concern the mechanisms that allow family members to go about their business without interference from their highly related siblings. Here I will discuss some insights from studies of the bZIP class of transcription factors.

scholarly journals Expression of Adhesive Pili and the Collagen-Binding Adhesin Ace Is Activated by ArgR Family Transcription Factors inEnterococcus faecalis

2018 ◽  
Vol 200 (18) ◽  
Author(s):  
Dawn A. Manias ◽  
Gary M. Dunny
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Enterococcus Faecalis ◽  
Opportunistic Infections ◽  
Structural Genes ◽  
Gene Encoding ◽  
Collagen Binding ◽  
Content Type ◽  
Surface Adhesins

ABSTRACTIt was shown previously that the disruption of theahrCgene encoding a predicted ArgR family transcription factor results in a severe defect in biofilm formationin vitro, as well as a significant attenuation of virulence ofEnterococcus faecalisstrain OG1RF in multiple experimental infection models. Using transcriptome sequencing (RNA-seq), we observedahrC-dependent changes in the expression of more than 20 genes. AhrC-repressed genes included predicted determinants of arginine catabolism and several other metabolic genes and predicted transporters, while AhrC-activated genes included determinants involved in the production of surface protein adhesins. Most notably, the structural and regulatory genes of theebplocus encoding adhesive pili were positively regulated, as well as theacegene, encoding a collagen-binding adhesin. UsinglacZtranscription reporter fusions, we determined thatahrCand a secondargRtranscription factor gene,argR2, both function to activate the expression ofebpR, which directly activates the transcription of the pilus structural genes. Our data suggest that in the wild-typeE. faecalis, the low levels of EbpR limit the expression of pili and that biofilm biomass is also limited by the amount of pili expressed by the bacteria. The expression ofaceis similarly enhanced by AhrC and ArgR2, butaceexpression is not dependent on EbpR. Our results demonstrate the existence of novel regulatory cascades controlled by a pair of ArgR family transcription factors that might function as a heteromeric protein complex.IMPORTANCECell surface adhesins play critical roles in the formation of biofilms, host colonization, and the pathogenesis of opportunistic infections byEnterococcus faecalis. Here, we present new results showing that the expression of two major enterococcal surface adhesins,ebppili, and the collagen-binding protein Ace is positively regulated at the transcription level by twoargRfamily transcription factors, AhrC and ArgR2. In the case of pili, the direct target of regulation is theebpRgene, previously shown to activate the transcription of the pilus structural genes, while the activation ofacetranscription appears to be directly impacted by the two ArgR proteins. These transcription factors may represent new targets for blocking enterococcal infections.

scholarly journals The PAX3-FKHR fusion protein created by the t(2;13) translocation in alveolar rhabdomyosarcomas is a more potent transcriptional activator than PAX3.

1995 ◽  
Vol 15 (3) ◽  
pp. 1522-1535 ◽  
Author(s):  
W J Fredericks ◽  
N Galili ◽  
S Mukhopadhyay ◽  
G Rovera ◽  
J Bennicelli ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Fusion Protein ◽  
Target Genes ◽  
Transcriptional Activator ◽  
Wild Type ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Pediatric Solid Tumors ◽  
Single Polypeptide

Alveolar rhabdomyosarcomas are pediatric solid tumors with a hallmark cytogenetic abnormality: translocation of chromosomes 2 and 13 [t(2;13) (q35;q14)]. The genes on each chromosome involved in this translocation have been identified as the transcription factor-encoding genes PAX3 and FKHR. The NH2-terminal paired box and homeodomain DNA-binding domains of PAX3 are fused in frame to COOH-terminal regions of the chromosome 13-derived FKHR gene, a novel member of the forkhead DNA-binding domain family. To determine the role of the fusion protein in transcriptional regulation and oncogenesis, we identified the PAX3-FKHR fusion protein and characterized its function(s) as a transcription factor relative to wild-type PAX3. Antisera specific to PAX3 and FKHR were developed and used to examine PAX3 and PAX3-FKHR expression in tumor cell lines. Sequential immunoprecipitations with anti-PAX3 and anti-FKHR sera demonstrated expression of a 97-kDa PAX3-FKHR fusion protein in the t(2;13)-positive rhabdomyosarcoma Rh30 cell line and verified that a single polypeptide contains epitopes derived from each protein. The PAX3-FKHR protein was localized to the nucleus in Rh30 cells, as was wild-type PAX3, in t(2;13)-negative A673 cells. In gel shift assays using a canonical PAX binding site (e5 sequence), we found that DNA binding of PAX3-FKHR was significantly impaired relative to that of PAX3 despite the two proteins having identical PAX DNA-binding domains. However, the PAX3-FKHR fusion protein was a much more potent transcriptional activator than PAX3 as determined by transient cotransfection assays using e5-CAT reporter plasmids. The PAX3-FKHR protein may function as an oncogenic transcription factor by enhanced activation of normal PAX3 target genes.

scholarly journals Regulation of Transcription by Hypoxia Requires a Multiprotein Complex That Includes Hypoxia-Inducible Factor 1, an Adjacent Transcription Factor, and p300/CREB Binding Protein

1998 ◽  
Vol 18 (7) ◽  
pp. 4089-4096 ◽  
Author(s):  
Benjamin L. Ebert ◽  
H. Franklin Bunn
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Dna Binding ◽  
Binding Proteins ◽  
Binding Protein ◽  
Hypoxia Inducible Factor ◽  
Dna Binding Proteins ◽  
Creb Binding Protein ◽  
Multiprotein Complex ◽  
Hypoxia Inducible Factor 1

ABSTRACT Molecular adaptation to hypoxia depends on the binding of hypoxia-inducible factor 1 (HIF-1) to cognate response elements in oxygen-regulated genes. In addition, adjacent sequences are required for hypoxia-inducible transcription. To investigate the mechanism of interaction between these cis-acting sequences, the multiprotein complex binding to the lactate dehydrogenase A (LDH-A) promoter was characterized. The involvement of HIF-1, CREB-1/ATF-1, and p300/CREB binding protein (CBP) was demonstrated by techniques documenting in vitro binding, in combination with transient transfections that test the in vivo functional importance of each protein. In both the LDH-A promoter and the erythropoietin 3′ enhancer, formation of multiprotein complexes was analyzed by using biotinylated probes encompassing functionally critical cis-acting sequences. Strong binding of p300/CBP required interactions with multiple DNA binding proteins. Thus, the necessity of transcription factor binding sites adjacent to a HIF-1 site for hypoxically inducible transcription may be due to the requirement of p300 to interact with multiple transcription factors for high-affinity binding and activation of transcription. Since it has been found to interact with a wide range of transcription factors, p300 is likely to play a similar role in other genes, mediating interactions between DNA binding proteins, thereby activating stimulus-specific and tissue-specific gene transcription.

Deletion and overexpression of the Aspergillus nidulans GATA factor AreB reveals unexpected pleiotropy

Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 3868-3880 ◽  
Author(s):  
Koon Ho Wong ◽  
Michael J. Hynes ◽  
Richard B. Todd ◽  
Meryl A. Davis
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Aspergillus Nidulans ◽  
Zinc Finger ◽  
Leucine Zipper ◽  
Binding Domain ◽  
Negative Regulator ◽  
Dna Binding Domain ◽  
Gata Factor ◽  
Nitrogen Acquisition

The Aspergillus nidulans transcription factor AreA is a key regulator of nitrogen metabolic gene expression. AreA contains a C-terminal GATA zinc finger DNA-binding domain and activates expression of genes necessary for nitrogen acquisition. Previous studies identified AreB as a potential negative regulator of nitrogen catabolism showing similarity with Penicillium chrysogenum NreB and Neurospora crassa ASD4. The areB gene encodes multiple products containing an N-terminal GATA zinc finger and a leucine zipper motif. We deleted the areB gene and now show that AreB negatively regulates AreA-dependent nitrogen catabolic gene expression under nitrogen-limiting or nitrogen-starvation conditions. AreB also acts pleiotropically, with functions in growth, conidial germination and asexual development, though not in sexual development. AreB overexpression results in severe growth inhibition, aberrant cell morphology and reduced AreA-dependent gene expression. Deletion of either the DNA-binding domain or the leucine zipper domain results in loss of both nitrogen and developmental phenotypes.

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