scholarly journals ACE4, a novel transcriptional activator involved in the regulation of cellulase genes on cellulose in Trichoderma reesei

2021 ◽  
Author(s):  
Yumeng Chen ◽  
Aibo Lin ◽  
Pei Liu ◽  
Xingjia Fan ◽  
Chuan Wu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Trichoderma Reesei ◽  
Transcriptional Activator ◽  
Cellulase Production ◽  
Comparative Genomic ◽  
Transcriptional Level ◽  
Cellulase Gene ◽  
Cellulase Expression

The filamentous fungus Trichoderma reesei is a model strain for cellulase production. Cellulase gene expression in T. reesei is controlled by multiple transcription factors. Here, we identified by comparative genomic screening a novel transcriptional activator ACE4 ( A ctivator of c ellulase e xpression 4) that positively regulates cellulase gene expression on cellulose in T. reesei . Disruption of the ace4 gene significantly decreased expression of four main cellulase genes, and the essential cellulase transcription factor encoding gene ace3 . Overexpression of ace4 increased cellulase production by approximately 22% compared to that in the parental strain. Further investigations using electrophoretic mobility shift assays, DNase I footprinting assays, and chromatin immunoprecipitation assays indicated that ACE4 directly binds to the promoter of cellulase genes by recognizing the two adjacent 5′-GGCC-3′ sequences. Additionally, ACE4 directly binds to the promoter of ace3 and, in turn, regulates the expression of ACE3 to facilitate cellulase production. Collectively, these results demonstrate an important role for ACE4 in regulating cellulase gene expression, which will contribute to understanding the mechanism underlying cellulase expression in T. reesei . IMPORTANCE T. reesei is commonly utilized in industry to produce cellulases, enzymes that degrade lignocellulosic biomass for the production of bioethanol and bio-based products. T. reesei is capable of rapidly initiating the biosynthesis of cellulases in the presence of cellulose, which has made it useful as a model fungus for studying gene expression in eukaryotes. Cellulase gene expression is controlled through multiple transcription factors at the transcriptional level. However, the molecular mechanisms by which transcription is controlled remain unclear. In the present study, we identified a novel transcription factor, ACE4, which regulates cellulase expression on cellulose by binding to the promoters of cellulase genes and the cellulase activator ace3 . Our study not only expands the general functional understanding of the novel transcription factor ACE4 but also provides evidence for the regulatory mechanism mediating gene expression in T. reesei .

scholarly journals Interdependent recruitment of CYC8/TUP1 and the transcriptional activator XYR1 at target promoters is required for induced cellulase gene expression in Trichoderma reesei

PLoS Genetics ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. e1009351
Author(s):  
Lei Wang ◽  
Weixin Zhang ◽  
Yanli Cao ◽  
Fanglin Zheng ◽  
Guolei Zhao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Trichoderma Reesei ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Gene Activation ◽  
Transcriptional Activator ◽  
Cellulase Production ◽  
Gene Promoters ◽  
Cellulase Gene ◽  
Histone H4

Cellulase production in filamentous fungus Trichoderma reesei is highly responsive to various environmental cues involving multiple positive and negative regulators. XYR1 (Xylanase regulator 1) has been identified as the key transcriptional activator of cellulase gene expression in T. reesei. However, the precise mechanism by which XYR1 achieves transcriptional activation of cellulase genes is still not fully understood. Here, we identified the TrCYC8/TUP1 complex as a novel coactivator for XYR1 in T. reesei. CYC8/TUP1 is the first identified transcriptional corepressor complex mediating repression of diverse genes in Saccharomyces cerevisiae. Knockdown of Trcyc8 or Trtup1 resulted in markedly impaired cellulase gene expression in T. reesei. We found that TrCYC8/TUP1 was recruited to cellulase gene promoters upon cellulose induction and this recruitment is dependent on XYR1. We further observed that repressed Trtup1 or Trcyc8 expression caused a strong defect in XYR1 occupancy and loss of histone H4 at cellulase gene promoters. The defects in XYR1 binding and transcriptional activation of target genes in Trtup1 or Trcyc8 repressed cells could not be overcome by XYR1 overexpression. Our results reveal a novel coactivator function for TrCYC8/TUP1 at the level of activator binding, and suggest a mechanism in which interdependent recruitment of XYR1 and TrCYC8/TUP1 to cellulase gene promoters represents an important regulatory circuit in ensuring the induced cellulase gene expression. These findings thus contribute to unveiling the intricate regulatory mechanism underlying XYR1-mediated cellulase gene activation and also provide an important clue that will help further improve cellulase production by T. reesei.

scholarly journals Understanding the Role of Trichoderma reesei Vib1 in Gene Expression during Cellulose Degradation

2021 ◽  
Vol 7 (8) ◽  
pp. 613
Author(s):  
Xiuzhen Chen ◽  
Bingran Song ◽  
Minglu Liu ◽  
Lina Qin ◽  
Zhiyang Dong
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Trichoderma Reesei ◽  
Cellulose Degradation ◽  
Strain Improvement ◽  
Cellulase Production ◽  
Oxidoreductase Activity ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Almost All

Vib1, a member of the Ndt80/PhoG-like transcription factor family, has been shown to be essential for cellulase production of Trichoderma reesei. Here, we combined transcriptomic and genetic analyses to gain mechanistic insights into the roles of Vib1 during cellulose degradation. Our transcriptome analysis showed that the vib1 deletion caused 586 genes with decreased expression and 431 genes with increased expression on cellulose. The downregulated genes were enriched for Gene Ontology terms associated with carbohydrate metabolism, transmembrane transport, oxidoreductase activity, and transcription factor activity. Of the 258 genes induced by cellulose, 229 showed no or decreased expression in Δvib1 on cellulose, including almost all (hemi)cellulase genes, crucial sugar transporter genes (IDs:69957, 3405), and the genes encoding main transcriptional activators Xyr1 and Ace3. Additionally, Vib1 also regulated the expression of genes involved in secondary metabolism. Further comparison of the transcriptomes of Δvib1 and Δxyr1 in cellulose revealed that the genes regulated by Vib1 had much overlap with Xyr1 targets especially for the gene set induced by cellulose, presumably whose expression requires the cooperativity between Vib1 and Xyr1. Genetic evidence indicated that Vib1 regulates cellulase gene expression partially via Xyr1. Our results will provide new clues for strain improvement.

Subnuclear compartmentalization of sequence-specific transcription factors and regulation of eukaryotic gene expression

2005 ◽  
Vol 83 (4) ◽  
pp. 535-547 ◽  
Author(s):  
Gareth N Corry ◽  
D Alan Underhill
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Current Knowledge ◽  
Nuclear Architecture ◽  
Subnuclear Localization ◽  
Modular Structures

To date, the majority of the research regarding eukaryotic transcription factors has focused on characterizing their function primarily through in vitro methods. These studies have revealed that transcription factors are essentially modular structures, containing separate regions that participate in such activities as DNA binding, protein–protein interaction, and transcriptional activation or repression. To fully comprehend the behavior of a given transcription factor, however, these domains must be analyzed in the context of the entire protein, and in certain cases the context of a multiprotein complex. Furthermore, it must be appreciated that transcription factors function in the nucleus, where they must contend with a variety of factors, including the nuclear architecture, chromatin domains, chromosome territories, and cell-cycle-associated processes. Recent examinations of transcription factors in the nucleus have clarified the behavior of these proteins in vivo and have increased our understanding of how gene expression is regulated in eukaryotes. Here, we review the current knowledge regarding sequence-specific transcription factor compartmentalization within the nucleus and discuss its impact on the regulation of such processes as activation or repression of gene expression and interaction with coregulatory factors.Key words: transcription, subnuclear localization, chromatin, gene expression, nuclear architecture.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals The Regulatory Mechanism of Water Activities on Aflatoxins Biosynthesis and Conidia Development, and Transcription Factor AtfB Is Involved in This Regulation

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 431
Author(s):  
Longxue Ma ◽  
Xu Li ◽  
Xiaoyun Ma ◽  
Qiang Yu ◽  
Xiaohua Yu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Environmental Factors ◽  
Health Risks ◽  
Sexual Development ◽  
Regulatory Mechanism ◽  
Food Storage ◽  
Economic Losses ◽  
Transcriptional Level ◽  
Conidia Production

Peanuts are frequently infected by Aspergillus strains and then contaminated by aflatoxins (AF), which brings out economic losses and health risks. AF production is affected by diverse environmental factors, especially water activity (aw). In this study, A. flavus was inoculated into peanuts with different aw (0.90, 0.95, and 0.99). Both AFB1 yield and conidia production showed the highest level in aw 0.90 treatment. Transcriptional level analyses indicated that AF biosynthesis genes, especially the middle- and later-stage genes, were significantly up-regulated in aw 0.90 than aw 0.95 and 0.99. AtfB could be the pivotal regulator response to aw variations, and could further regulate downstream genes, especially AF biosynthesis genes. The expressions of conidia genes and relevant regulators were also more up-regulated at aw 0.90 than aw 0.95 and 0.99, suggesting that the relative lower aw could increase A. flavus conidia development. Furthermore, transcription factors involved in sexual development and nitrogen metabolism were also modulated by different aw. This research partly clarified the regulatory mechanism of aw on AF biosynthesis and A. flavus development and it would supply some advice for AF prevention in food storage.

scholarly journals Candida albicans Ferric Reductases Are Differentially Regulated in Response to Distinct Forms of Iron Limitation by the Rim101 and CBF Transcription Factors

2008 ◽  
Vol 7 (7) ◽  
pp. 1168-1179 ◽  
Author(s):  
Yong-Un Baek ◽  
Mingchun Li ◽  
Dana A. Davis
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Transcription Factors ◽  
Iron Acquisition ◽  
Mammalian Host ◽  
Regulatory Sequence ◽  
Ferric Reductase ◽  
Reductase Gene ◽  
Ferric Reductases

ABSTRACT Iron is an essential nutrient that is severely limited in the mammalian host. Candida albicans encodes a family of 15 putative ferric reductases, which are required for iron acquisition and utilization. Despite the central role of ferric reductases in iron acquisition and mobilization, relatively little is known about the regulatory networks that govern ferric reductase gene expression in C. albicans. Here we have demonstrated the differential regulation of two ferric reductases, FRE2 and FRP1, in response to distinct iron-limited environments. FRE2 and FRP1 are both induced in alkaline-pH environments directly by the Rim101 transcription factor. However, FRP1 but not FRE2 is also induced by iron chelation. We have identified a CCAAT motif as the critical regulatory sequence for chelator-mediated induction and have found that the CCAAT binding factor (CBF) is essential for FRP1 expression in iron-limited environments. We found that a hap5Δ/hap5Δ mutant, which disrupts the core DNA binding activity of CBF, is unable to grow under iron-limited conditions. C. albicans encodes three CBF-dependent transcription factors, and we identified the Hap43 protein as the CBF-dependent transcription factor required for iron-limited responses. These studies provide key insights into the regulation of ferric reductase gene expression in the fungal pathogen C. albicans.

CLR-4, a novel conserved transcription factor for cellulase gene expression in ascomycete fungi

2018 ◽  
Vol 111 (2) ◽  
pp. 373-394 ◽  
Author(s):  
Qian Liu ◽  
Jingen Li ◽  
Ranran Gao ◽  
Jinyang Li ◽  
Guoli Ma ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Cellulase Gene ◽  
Ascomycete Fungi

scholarly journals Single Cell Transcriptomic Analysis of Spinal Dmrt3 Neurons in Zebrafish and Mouse Identifies Distinct Subtypes and Reveal Novel Subpopulations Within the dI6 Domain

2021 ◽  
Vol 15 ◽  
Author(s):  
Ana Belén Iglesias González ◽  
Jon E. T. Jakobsson ◽  
Jennifer Vieillard ◽  
Malin C. Lagerström ◽  
Klas Kullander ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Axon Guidance ◽  
Single Cell ◽  
Cellular Activity ◽  
Electrophysiological Properties ◽  
Related Transcription Factor ◽  
Unique Markers ◽  
Molecular Code

The spinal locomotor network is frequently used for studies into how neuronal circuits are formed and how cellular activity shape behavioral patterns. A population of dI6 interneurons, marked by the Doublesex and mab-3 related transcription factor 3 (Dmrt3), has been shown to participate in the coordination of locomotion and gaits in horses, mice and zebrafish. Analyses of Dmrt3 neurons based on morphology, functionality and the expression of transcription factors have identified different subtypes. Here we analyzed the transcriptomes of individual cells belonging to the Dmrt3 lineage from zebrafish and mice to unravel the molecular code that underlies their subfunctionalization. Indeed, clustering of Dmrt3 neurons based on their gene expression verified known subtypes and revealed novel populations expressing unique markers. Differences in birth order, differential expression of axon guidance genes, neurotransmitters, and their receptors, as well as genes affecting electrophysiological properties, were identified as factors likely underlying diversity. In addition, the comparison between fish and mice populations offers insights into the evolutionary driven subspecialization concomitant with the emergence of limbed locomotion.

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