DNA affinity purification sequencing and transcriptional profiling reveal new aspects of nitrogen regulation in a filamentous fungus

Sensing available nutrients and efficiently utilizing them is a challenge common to all organisms. The model filamentous fungus Neurospora crassa is capable of utilizing a variety of inorganic and organic nitrogen sources. Nitrogen utilization in N. crassa is regulated by a network of pathway-specific transcription factors that activate genes necessary to utilize specific nitrogen sources in combination with nitrogen catabolite repression regulatory proteins. We identified an uncharacterized pathway-specific transcription factor, amn-1, that is required for utilization of the nonpreferred nitrogen sources proline, branched-chain amino acids, and aromatic amino acids. AMN-1 also plays a role in regulating genes involved in responding to the simple sugar mannose, suggesting an integration of nitrogen and carbon metabolism. The utilization of nonpreferred nitrogen sources, which require metabolic processing before being used as a nitrogen source, is also regulated by the nitrogen catabolite regulator NIT-2. Using RNA sequencing combined with DNA affinity purification sequencing, we performed a survey of the role of NIT-2 and the pathway-specific transcription factors NIT-4 and AMN-1 in directly regulating genes involved in nitrogen utilization. Although previous studies suggested promoter binding by both a pathway-specific transcription factor and NIT-2 may be necessary for activation of nitrogen-responsive genes, our data show that pathway-specific transcription factors regulate genes involved in the catabolism of specific nitrogen sources, while NIT-2 regulates genes involved in utilization of all nonpreferred nitrogen sources, such as nitrogen transporters. Together, these transcription factors form a nutrient sensing network that allows N. crassa cells to regulate nitrogen utilization.

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The Prodomain of Ssy5 Protease Controls Receptor-Activated Proteolysis of Transcription Factor Stp1

Molecular and Cellular Biology ◽

10.1128/mcb.00323-10 ◽

2010 ◽

Vol 30 (13) ◽

pp. 3299-3309 ◽

Cited By ~ 26

Author(s):

Thorsten Pfirrmann ◽

Stijn Heessen ◽

Deike J. Omnus ◽

Claes Andréasson ◽

Per O. Ljungdahl

Keyword(s):

Amino Acids ◽

Transcription Factor ◽

Transcription Factors ◽

Amino Acid ◽

Signaling Pathway ◽

Temperature Control ◽

Regulatory Mechanism ◽

Potent Inhibitor ◽

Large N

ABSTRACT Extracellular amino acids induce the yeast SPS sensor to endoproteolytically cleave transcription factors Stp1 and Stp2 in a process termed receptor-activated proteolysis (RAP). Ssy5, the activating endoprotease, is synthesized with a large N-terminal prodomain and a C-terminal chymotrypsin-like catalytic (Cat) domain. During biogenesis, Ssy5 cleaves itself and the prodomain and Cat domain remain associated, forming an inactive primed protease. Here we show that the prodomain is a potent inhibitor of Cat domain activity and that its inactivation is a requisite for RAP. Accordingly, amino acid-induced signals trigger proteasome-dependent degradation of the prodomain. A mutation that stabilizes the prodomain prevents Stp1 processing, whereas destabilizing mutations lead to constitutive RAP-independent Stp1 processing. We fused a conditional degron to the prodomain to synthetically reprogram the amino acid-responsive SPS signaling pathway, placing it under temperature control. Our results define a regulatory mechanism that is novel for eukaryotic proteases functioning within cells.

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The External Amino Acid Signaling Pathway Promotes Activation of Stp1 and Uga35/Dal81 Transcription Factors for Induction of the AGP1 Gene in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/166.4.1727 ◽

2004 ◽

Vol 166 (4) ◽

pp. 1727-1739 ◽

Cited By ~ 1

Author(s):

Fadi Abdel-Sater ◽

Ismaïl Iraqui ◽

Antonio Urrestarazu ◽

Bruno André

Keyword(s):

Amino Acids ◽

Transcription Factor ◽

Transcription Factors ◽

Amino Acid ◽

Signaling Pathway ◽

Nitrogen Supply ◽

Upstream Region ◽

Gata Factor ◽

Amino Acid Permease ◽

Amino Acid Signaling

Abstract Yeast cells respond to the presence of amino acids in their environment by inducing transcription of several amino acid permease genes including AGP1, BAP2, and BAP3. The signaling pathway responsible for this induction involves Ssy1, a permease-like sensor of external amino acids, and culminates with proteolytic cleavage and translocation to the nucleus of the zinc-finger proteins Stp1 and Stp2, the lack of which abolishes induction of BAP2 and BAP3. Here we show that Stp1—but not Stp2—plays an important role in AGP1 induction, although significant induction of AGP1 by amino acids persists in stp1 and stp1 stp2 mutants. This residual induction depends on the Uga35/Dal81 transcription factor, indicating that the external amino acid signaling pathway activates not only Stp1 and Stp2, but also another Uga35/Dal81-dependent transcriptional circuit. Analysis of the AGP1 gene’s upstream region revealed that Stp1 and Uga35/Dal81 act synergistically through a 21-bp cis-acting sequence similar to the UASAA element previously found in the BAP2 and BAP3 upstream regions. Although cells growing under poor nitrogen-supply conditions display much higher induction of AGP1 expression than cells growing under good nitrogen-supply conditions, the UASAA itself is totally insensitive to nitrogen availability. Nitrogen-source control of AGP1 induction is mediated by the GATA factor Gln3, likely acting through adjacent 5′-GATA-3′ sequences, to amplify the positive effect of UASAA. Our data indicate that Stp1 may act in combination with distinct sets of transcription factors, according to the gene context, to promote induction of transcription in response to external amino acids. The data also suggest that Uga35/Dal81 is yet another transcription factor under the control of the external amino acid sensing pathway. Finally, the data show that the TOR pathway mediating global nitrogen control of transcription does not interfere with the external amino acid signaling pathway.

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Transcriptome profilings reveal the candidate genes, pathways and transcription factors related to nitrogen utilization and excessive nitrogen stress in perennial ryegrass.

10.21203/rs.3.rs-25633/v1 ◽

2020 ◽

Author(s):

Yinruizhi Li ◽

Mengdi Wang ◽

Ke Teng ◽

Di Dong ◽

Zhuocheng Liu ◽

...

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Perennial Ryegrass ◽

Expression Patterns ◽

Enrichment Analysis ◽

Nitrogen Utilization ◽

Utilization Rate ◽

Nitrogen Stress ◽

Molecular Response ◽

Stress Effect

Abstract Background：Lolium perenne L. is a kind of high quality forage grass, which can provide a good nutritional basis for herbivorous livestock. However, how to improve the nitrogen utilization rate of ryegrass and avoid the nitrate toxicity caused by excessive nitrogen has been troubling people for a long time. Up to now, the molecular response mechanism of ryegrass to nitrogen is not clear, especially under the condition of excessive nitrogen. Based on this, we tried to obtain a new insight into molecular response of ryegrass in nitrogen utilization and excessive nitrogen stress, providing the molecular theoretical basis for solving this problem.Results: In this study, the transcription of perennial ryegrass at different nitrogen levels was identified by high-throughput next-generation DNA sequencing. Phenotypic characterizations investigated that ryegrass in treatment N0.5 has a better growth state than the other three groups. The treatment N1 and N10 contained excessive nitrogen, which had a stress effect on plant growth. Analysis of differentially expressed genes indicated that 345, 105 genes are considered to involve in the regulation of nitrogen utilization and excessive nitrogen stress, respectively. GO enrichment analysis revealed that plant response to nitrogen mainly enrich in two categories, including “biological process” and “molecular function”. KEGG enrichment analysis suggested that “Photosynthesis-antenna proteins” may respond positively to nitrogen under appropriate nitrogen conditions, whereas “steroid biosynthesis”, “carotenoid biosynthesis” and “C5-branched dibasic acid metabolism” had been identified as top significant enrichment pathways response to excessive nitrogen. Transcription factors analysis showed that 21 TFs related to nitrogen utilization were classified into 10 transcription factor families, especially AP2-EREBP and MYB TF families. 4 TFs related to excessive nitrogen stress were identified, which belonged to 4 transcription factor families including LOB, NAC, AP2-EREBP and HB. The expression patterns of these selected genes above were also analyzed. Conclusions: These results made a contribution to comprehend the molecular mechanism of perennial ryegrass response to nitrogen. It provides new ideas for guiding the production practice and variety improvement of forage and even food crops from the perspective of molecular biology.

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Global analysis of the RpaB regulon based on the positional distribution of HLR1 sequences and comparative differential RNA-Seq data

10.1101/443713 ◽

2018 ◽

Author(s):

Matthias Riediger ◽

Taro Kadowaki ◽

Ryuta Nagayama ◽

Jens Georg ◽

Yukako Hihara ◽

...

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Transcriptional Activation ◽

Target Genes ◽

Global Analysis ◽

Affinity Purification ◽

Electron Flow ◽

Positional Distribution ◽

State Transitions ◽

Northern Hybridization

ABSTRACTThe transcription factor RpaB regulates the expression of genes encoding photosynthesis-associated proteins during light acclimation. The binding site of RpaB is the HLR1 motif, a pair of imperfect octameric direct repeats, separated by two random nucleotides. Here, we used high-resolution mapping data of transcriptional start sites (TSSs) in the modelSynechocystissp. PCC 6803 in conjunction with the positional distribution of HLR1 sites for the global prediction of the RpaB regulon. The results demonstrate that RpaB regulates the expression of more than 150 promoters, driving the transcription of protein-coding and non-coding genes and antisense transcripts under low light and upon the shift to high light when DNA binding activity is lost. Transcriptional activation by RpaB is achieved when the HLR1 motif is located 66 to 45 nt upstream, repression occurs when it is close to or overlapping the TSS. Selected examples were validated by multiple experimental approaches, including chromatin affinity purification, reporter gene, northern hybridization and electrophoretic mobility shift assays. We found that RpaB controlsssr2016/pgr5, which is involved in cyclic electron flow and state transitions; six out of nine ferredoxins; three of four FtsH proteases;gcvP/slr0293, encoding a crucial photorespiratory protein; andnirAandisiAfor which we suggest cross-regulation with the transcription factors NtcA or FurA, respectively. In addition to photosynthetic gene functions, RpaB contributes to the control of genes affiliated with nitrogen assimilation, cofactor biosyntheses, the CRISPR system and the circadian clock, making it one of the most versatile regulators in cyanobacteria.Significance StatementRpaB is a transcription factor in cyanobacteria and in the chloroplasts of several lineages of eukaryotic algae. Like other important transcription factors, the gene encoding RpaB cannot be deleted, making the study of deletion mutants impossible. Based on a bioinformatic approach, we increased the number of known genes controlled by RpaB by a factor of 5. Depending on the distance to the TSS, RpaB mediates transcriptional activation or repression. The high number and functional diversity among its target genes and co-regulation with other transcriptional regulators characterize RpaB as a regulatory hub.

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Determining Aspergillus fumigatus transcription factor expression and function during invasion of the mammalian lung

PLoS Pathogens ◽

10.1371/journal.ppat.1009235 ◽

2021 ◽

Vol 17 (3) ◽

pp. e1009235

Author(s):

Hong Liu ◽

Wenjie Xu ◽

Vincent M. Bruno ◽

Quynh T. Phan ◽

Norma V. Solis ◽

...

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Aspergillus Fumigatus ◽

Transcriptional Profiling ◽

Transcriptional Response ◽

Gene Clusters ◽

Transcription Factor Genes ◽

And Function

To gain a better understanding of the transcriptional response of Aspergillus fumigatus during invasive pulmonary infection, we used a NanoString nCounter to assess the transcript levels of 467 A. fumigatus genes during growth in the lungs of immunosuppressed mice. These genes included ones known to respond to diverse environmental conditions and those encoding most transcription factors in the A. fumigatus genome. We found that invasive growth in vivo induces a unique transcriptional profile as the organism responds to nutrient limitation and attack by host phagocytes. This in vivo transcriptional response is largely mimicked by in vitro growth in Aspergillus minimal medium that is deficient in nitrogen, iron, and/or zinc. From the transcriptional profiling data, we selected 9 transcription factor genes that were either highly expressed or strongly up-regulated during in vivo growth. Deletion mutants were constructed for each of these genes and assessed for virulence in mice. Two transcription factor genes were found to be required for maximal virulence. One was rlmA, which is required for the organism to achieve maximal fungal burden in the lung. The other was sltA, which regulates of the expression of multiple secondary metabolite gene clusters and mycotoxin genes independently of laeA. Using deletion and overexpression mutants, we determined that the attenuated virulence of the ΔsltA mutant is due in part to decreased expression aspf1, which specifies a ribotoxin, but is not mediated by reduced expression of the fumigaclavine gene cluster or the fumagillin-pseruotin supercluster. Thus, in vivo transcriptional profiling focused on transcription factors genes provides a facile approach to identifying novel virulence regulators.

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Landscape of allele-specific transcription factor binding in the human genome

10.1101/2020.10.07.327643 ◽

2020 ◽

Cited By ~ 1

Author(s):

Sergey Abramov ◽

Alexandr Boytsov ◽

Dariia Bykova ◽

Dmitry D. Penzar ◽

Ivan Yevshin ◽

...

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Molecular Mechanisms ◽

Specific Binding ◽

Transcription Factor Binding ◽

Single Nucleotide Variants ◽

Single Nucleotide ◽

Specific Transcription Factor ◽

Factor Binding ◽

Allele Specific

AbstractSequence variants in gene regulatory regions alter gene expression and contribute to phenotypes of individual cells and the whole organism, including disease susceptibility and progression. Single-nucleotide variants in enhancers or promoters may affect gene transcription by altering transcription factor binding sites. Differential transcription factor binding in heterozygous genomic loci provides a natural source of information on such regulatory variants. We present a novel approach to call the allele-specific transcription factor binding events at single-nucleotide variants in ChIP-Seq data, taking into account the joint contribution of aneuploidy and local copy number variation, that is estimated directly from variant calls. We have conducted a meta-analysis of more than 7 thousand ChIP-Seq experiments and assembled the database of allele-specific binding events listing more than half a million entries at nearly 270 thousand single-nucleotide polymorphisms for several hundred human transcription factors and cell types. These polymorphisms are enriched for associations with phenotypes of medical relevance and often overlap eQTLs, making candidates for causality by linking variants with molecular mechanisms. Specifically, there is a special class of switching sites, where different transcription factors preferably bind alternative alleles, thus revealing allele-specific rewiring of molecular circuitry.

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Determining Aspergillus fumigatus transcription factor expression and function during invasion of the mammalian lung

10.1101/2020.12.23.424128 ◽

2020 ◽

Author(s):

Hong Liu ◽

Wenjie Xu ◽

Vincent M. Bruno ◽

Quynh T. Phan ◽

Norma V. Solis ◽

...

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Secondary Metabolites ◽

Invasive Aspergillosis ◽

Aspergillus Fumigatus ◽

Transcriptional Profiling ◽

Transcriptional Response ◽

Transcription Factor Genes

AbstractTo gain a better understanding of the transcriptional response of Aspergillus fumigatus during invasive pulmonary infection, we used a NanoString nCounter to assess the transcript levels of 467 A. fumigatus genes during growth in the lungs of immunosuppressed mice. These genes included ones known to respond to diverse environmental conditions and those encoding most transcription factors in the A. fumigatus genome. We found that invasive growth in vivo induces a unique transcriptional profile as the organism responds to nutrient limitation and attack by host phagocytes. This in vivo transcriptional response is largely mimicked by in vitro growth in Aspergillus minimal medium that is deficient in nitrogen, iron, and/or zinc. From the transcriptional profiling data, we selected 9 transcription factor genes that were either highly expressed or strongly up-regulated during in vivo growth. Deletion mutants were constructed for each of these genes and assessed for virulence in mice. Two transcription factor genes were found to be required for maximal virulence. One was rlmA, which governs the ability of the organism to proliferate in the lung. The other was ace1, which regulates of the expression of multiple secondary metabolite gene clusters and mycotoxin genes independently of laeA. Using deletion and overexpression mutants, we determined that the attenuated virulence of the Δace1 mutant is due to decreased expression aspf1, which specifies a ribotoxin, but is not mediated by reduced expression of the fumigaclavine gene cluster or the fumagillin-pseruotin supercluster. Thus, in vivo transcriptional profiling focused on transcription factors genes provides a facile approach to identifying novel virulence regulators.Author summaryAlthough A. fumigatus causes the majority of cases of invasive aspergillosis, the function of most of the genes in its genome remains unknown. To identify genes encoding transcription factors that may be important for virulence, we used a NanoString nCounter to measure the mRNA levels of A. fumigatus transcription factor genes in the lungs of mice with invasive aspergillosis. The transcriptional profiling data indicate that the organism is exposed to nutrient limitation and stress during growth in the lungs, and that it responds by up-regulating genes that encode mycotoxins and secondary metabolites. In vitro, this response was most closely mimicked by growth in medium that was deficient in nitrogen, iron and/or zinc. Using the transcriptional profiling data, we identified two transcription factors that govern A. fumigatus virulence. These were RlmA, which is governs proliferation in the lung and Ace1, which controls the production of mycotoxins and secondary metabolites.

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Identification of transcription factors MYC and C/EBPβ mediated regulatory networks in heart failure

10.21203/rs.2.16967/v1 ◽

2019 ◽

Author(s):

Haiwei Wang ◽

Xinrui Wang ◽

Liangpu Xu ◽

Hua Cao

Keyword(s):

Heart Failure ◽

Transcription Factor ◽

Transcription Factors ◽

Signaling Pathway ◽

Insulin Signaling ◽

Regulatory Networks ◽

Target Genes ◽

Transcriptional Profiling ◽

Normal Heart ◽

Developmental Progress

Abstract Background: Heart failure is one of leading cause of death worldwide. However, the transcriptional profiling of heart failure is unclear. Moreover, the signaling pathways and transcription factors involving the heart failure developmental progress also are largely unclear.Methods: The transcriptional profiling of heart failure was identified from integrated gene expression datasets. The enriched pathways and transcription factors were analyzed using DAVID and GSEA assay. The transcriptional networks were created by Cytoscape.Results: Compared with the normal heart tissues, we found 90 genes were particularly differentially expressed in heart failing tissues, and those genes were associated with multiple metabolism pathways and insulin signaling pathway. Metabolism and insulin signaling pathway were both inactivated in heart failing tissues. Transcription factors MYC and C/EBPβ were both negatively associated with the expression profiling of heart failing tissues in GSEA assay. Moreover, compared with normal heart tissues, MYC and C/EBPβ were down regulated in heart failing tissues. Furthermore, MYC and C/EBPβ mediated downstream target genes were decreased in heart failing tissues. MYC and C/EBPβ were positively correlated with each other. At last, we constructed the transcription factor MYC and C/EBPβ mediated regulatory networks in heart failing tissues, and identified the MYC and C/EBPβ target genes which had been reported involving the failure developmental progress by literature research. Conclusions: Our results suggested that transcription factor MYC and C/EBPβ played critical roles in heart failure developmental progress. And new heart failure treatments may be developed by targeting MYC and C/EBPβ.

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Transcription factors involved in abiotic stress responses in maize (Zea mays L.) and their roles in enhanced productivity in the post genomics era

10.7287/peerj.preprints.27549v1 ◽

2019 ◽

Author(s):

Roy Njoroge Kimotho ◽

Elamin Hafiz Baillo ◽

Zhengbin Zhang

Keyword(s):

Zea Mays ◽

Transcription Factor ◽

Transcription Factors ◽

Abiotic Stress ◽

Stress Responses ◽

Abiotic Stresses ◽

Target Genes ◽

Animal Feed ◽

Specific Transcription Factor ◽

Transcription Factor Genes

Background: Maize (Zea mays L.) is a principal cereal crop cultivated worldwide for human food, animal feed, and more recently as a source of biofuel. However, as a direct consequence of water insufficiency and climate change, frequent occurrences of both biotic and abiotic stresses have been reported in different regions around the world, and recently, this has become a major threat in increasing global maize yields. Plants respond to abiotic stresses by utilizing the activity of transcription factors, which are families of genes coding for specific transcription factor proteins whose target genes form a regulon which is involved in the repression/ activation of genes associated with abiotic stress responses. Therefore, it is of uttermost importance to have a systematic study on each family of the transcription factors, the downstream target genes they regulate, and the specific transcription factor genes which are involved in multiple abiotic stress responses in maize and other main crops. Method: In this review, the main transcription factor families, the specific transcription factor genes and their regulons which are involved in abiotic stress regulation will be momentarily discussed. Great emphasis will be given on maize abiotic stress improvement throughout this review, although other examples from other plants like rice, Arabidopsis, wheat, and barley will be used. Results: We have described in detail the main transcription factor families in maize which take part in abiotic stress responses together with their regulons. Furthermore, we have also briefly described the utilization of high-efficiency technologies in the study and characterization of TFs involved in the abiotic stress regulatory networks in plants with an emphasis on increasing maize production. Examples of these technologies include next-generation sequencing, microarray analysis, machine learning and RNA-Seq technology. Conclusion: In conclusion, it is hoped that all the information provided in this review may in time contribute to the use of TF genes in the research, breeding, and development of new abiotic stress tolerant maize cultivars.

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