scholarly journals Hungry for Sex: Differential Roles for Ustilago maydisb Locus Components in Haploid Cells vis à vis Nutritional Availability

2021 ◽  
Vol 7 (2) ◽  
pp. 135
Author(s):  
R. Margaret Wallen ◽  
Kirsten Richardson ◽  
Madison Furnish ◽  
Hector Mendoza ◽  
Allison Dentinger ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Fusion ◽  
Nitrogen Starvation ◽  
B Locus ◽  
Self Recognition ◽  
Receptor Interactions ◽  
Maize Plants ◽  
The Individual ◽  
Eukaryotic Organisms ◽  
Nitrogen Sensing

Mating-types allow single-celled eukaryotic organisms to distinguish self from non-self in preparation for sexual reproduction. The components of mating-type loci provide initial self/non-self-recognition through pheromone and receptor interactions that control early cell fusion events. However, they may also provide a second level of scrutiny that requires differences in alleles leading to production of a transcription factor required for successful downstream developmental pathways after initial cell fusion. Interestingly, the protein subunits of these transcription factors have not been thoroughly examined for their roles, if any, in the haploid cells themselves. In Ustilago maydis, the causative agent of galls in maize plants, the b locus, encoding bEast (bE) and bWest (bW), components of the eventual requisite transcription factor, has been extensively studied for its role in formation of the stable dikaryon after mating and subsequent pathogenic program. Little is known, however, about any roles for bE or bW in haploid cells. Since mating in fungi is often induced under conditions of nitrogen starvation, we have explored connections between the b locus and the nitrogen-sensing and response pathways in U. maydis. We previously identified a connection in haploid cells between the b locus and Ump2, the high-affinity transceptor, a protein that both transports ammonium and triggers filamentous growth as a response to nitrogen starvation. Deletion of the entire b locus abrogates the filamentous response to low ammonium, a phenotype that is rescued by overexpression of Ump2. Here we further investigated the individual roles of bE and bW in haploid cells. We show that bE and bW are expressed differentially in haploid cells starved for ammonium. Their respective deletion elicits different effects on transcription of mating and pathogenic-related genes and, importantly, on the degree of pathogenic development in host plants. This is the first demonstration of a role for these mating locus components on haploid development and the first to demonstrate a connection to the ammonium transceptors.

scholarly journals trans-dominant mutants of E1A provide genetic evidence that the zinc finger of the trans-activating domain binds a transcription factor.

1991 ◽  
Vol 11 (9) ◽  
pp. 4287-4296 ◽  
Author(s):  
L C Webster ◽  
R P Ricciardi
Keyword(s):  
Transcription Factor ◽  
Zinc Finger ◽  
Cellular Protein ◽  
Site Directed Mutagenesis ◽  
Cellular Transcription Factor ◽  
Dominant Phenotype ◽  
Cellular Genes ◽  
Critical Residue ◽  
The Individual ◽  
Cellular Transcription

The 289R E1A protein of adenovirus stimulates transcription of early viral and certain cellular genes. trans-Activation requires residues 140 to 188, which encompass a zinc finger. Several studies have indicated that trans-activation by E1A is mediated through cellular transcription factors. In particular, the ability of the trans-dominant E1A point mutant hr5 (Ser-185 to Asn) to inhibit wild-type E1A trans-activation was proposed to result from the sequestration of a cellular factor. Using site-directed mutagenesis, we individually replaced every residue within and flanking the trans-activating domain with a conservative amino acid, revealing 16 critical residues. Six of the individual substitutions lying in a contiguous stretch C terminal to the zinc finger (carboxyl region183-188) imparted a trans-dominant phenotype. trans-Dominance was even produced by deletion of the entire carboxyl region183-188. Conversely, an intact finger region147-177 was absolutely required for trans-dominance, since second-site substitution of every critical residue in this region abrogated the trans-dominant phenotype of the hr5 protein. These data indicate that the finger region147-177 bind a limiting cellular transcription factor and that the carboxyl region183-188 provides a separate and essential function. In addition, we show that four negatively charged residues within the trans-activating domain do not comprise a distinct acidic activating region. We present a model in which the trans-activating domain of E1A binds to two different cellular protein targets through the finger and carboxyl regions.

scholarly journals Structural basis for the allosteric control of the global transcription factor NtcA by the nitrogen starvation signal 2-oxoglutarate

2010 ◽  
Vol 107 (28) ◽  
pp. 12487-12492 ◽  
Author(s):  
Meng-Xi Zhao ◽  
Yong-Liang Jiang ◽  
Yong-Xing He ◽  
Yi-Fei Chen ◽  
Yan-Bin Teng ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nitrogen Starvation ◽  
Structural Basis ◽  
Allosteric Control

trans-dominant mutants of E1A provide genetic evidence that the zinc finger of the trans-activating domain binds a transcription factor

1991 ◽  
Vol 11 (9) ◽  
pp. 4287-4296
Author(s):  
L C Webster ◽  
R P Ricciardi
Keyword(s):  
Transcription Factor ◽  
Zinc Finger ◽  
Cellular Protein ◽  
Site Directed Mutagenesis ◽  
Cellular Transcription Factor ◽  
Dominant Phenotype ◽  
Cellular Genes ◽  
Critical Residue ◽  
The Individual ◽  
Cellular Transcription

The 289R E1A protein of adenovirus stimulates transcription of early viral and certain cellular genes. trans-Activation requires residues 140 to 188, which encompass a zinc finger. Several studies have indicated that trans-activation by E1A is mediated through cellular transcription factors. In particular, the ability of the trans-dominant E1A point mutant hr5 (Ser-185 to Asn) to inhibit wild-type E1A trans-activation was proposed to result from the sequestration of a cellular factor. Using site-directed mutagenesis, we individually replaced every residue within and flanking the trans-activating domain with a conservative amino acid, revealing 16 critical residues. Six of the individual substitutions lying in a contiguous stretch C terminal to the zinc finger (carboxyl region183-188) imparted a trans-dominant phenotype. trans-Dominance was even produced by deletion of the entire carboxyl region183-188. Conversely, an intact finger region147-177 was absolutely required for trans-dominance, since second-site substitution of every critical residue in this region abrogated the trans-dominant phenotype of the hr5 protein. These data indicate that the finger region147-177 bind a limiting cellular transcription factor and that the carboxyl region183-188 provides a separate and essential function. In addition, we show that four negatively charged residues within the trans-activating domain do not comprise a distinct acidic activating region. We present a model in which the trans-activating domain of E1A binds to two different cellular protein targets through the finger and carboxyl regions.

scholarly journals Transcription-independent TFIIIC-bound sites cluster near heterochromatin boundaries within lamina-associated domains in C. elegans

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Alexis V. Stutzman ◽  
April S. Liang ◽  
Vera Beilinson ◽  
Kohta Ikegami
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Mammalian Cells ◽  
Sex Chromosome ◽  
Rna Polymerase Iii ◽  
Chromatin Organization ◽  
Control Of Gene Expression ◽  
C Elegans ◽  
Polymerase Iii ◽  
The Individual

Abstract Background Chromatin organization is central to precise control of gene expression. In various eukaryotic species, domains of pervasive cis-chromatin interactions demarcate functional domains of the genomes. In nematode Caenorhabditis elegans, however, pervasive chromatin contact domains are limited to the dosage-compensated sex chromosome, leaving the principle of C. elegans chromatin organization unclear. Transcription factor III C (TFIIIC) is a basal transcription factor complex for RNA polymerase III, and is implicated in chromatin organization. TFIIIC binding without RNA polymerase III co-occupancy, referred to as extra-TFIIIC binding, has been implicated in insulating active and inactive chromatin domains in yeasts, flies, and mammalian cells. Whether extra-TFIIIC sites are present and contribute to chromatin organization in C. elegans remains unknown. Results We identified 504 TFIIIC-bound sites absent of RNA polymerase III and TATA-binding protein co-occupancy characteristic of extra-TFIIIC sites in C. elegans embryos. Extra-TFIIIC sites constituted half of all identified TFIIIC binding sites in the genome. Extra-TFIIIC sites formed dense clusters in cis. The clusters of extra-TFIIIC sites were highly over-represented within the distal arm domains of the autosomes that presented a high level of heterochromatin-associated histone H3K9 trimethylation (H3K9me3). Furthermore, extra-TFIIIC clusters were embedded in the lamina-associated domains. Despite the heterochromatin environment of extra-TFIIIC sites, the individual clusters of extra-TFIIIC sites were devoid of and resided near the individual H3K9me3-marked regions. Conclusion Clusters of extra-TFIIIC sites were pervasive in the arm domains of C. elegans autosomes, near the outer boundaries of H3K9me3-marked regions. Given the reported activity of extra-TFIIIC sites in heterochromatin insulation in yeasts, our observation raised the possibility that TFIIIC may also demarcate heterochromatin in C. elegans.

scholarly journals Basic Helix-Loop-Helix (bHLH) Transcription Factors Regulate a Wide Range of Functions in Arabidopsis

2021 ◽  
Vol 22 (13) ◽  
pp. 7152
Author(s):  
Yaqi Hao ◽  
Xiumei Zong ◽  
Pan Ren ◽  
Yuqi Qian ◽  
Aigen Fu
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Target Genes ◽  
Gene Families ◽  
Bhlh Transcription Factor ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Wide Range ◽  
Range Of Functions ◽  
Eukaryotic Organisms

The basic helix-loop-helix (bHLH) transcription factor family is one of the largest transcription factor gene families in Arabidopsis thaliana, and contains a bHLH motif that is highly conserved throughout eukaryotic organisms. Members of this family have two conserved motifs, a basic DNA binding region and a helix-loop-helix (HLH) region. These proteins containing bHLH domain usually act as homo- or heterodimers to regulate the expression of their target genes, which are involved in many physiological processes and have a broad range of functions in biosynthesis, metabolism and transduction of plant hormones. Although there are a number of articles on different aspects to provide detailed information on this family in plants, an overall summary is not available. In this review, we summarize various aspects of related studies that provide an overview of insights into the pleiotropic regulatory roles of these transcription factors in plant growth and development, stress response, biochemical functions and the web of signaling networks. We then provide an overview of the functional profile of the bHLH family and the regulatory mechanisms of other proteins.

scholarly journals A Novel Transcription Factor, ERD15 (Early Responsive to Dehydration 15), Connects Endoplasmic Reticulum Stress with an Osmotic Stress-induced Cell Death Signal

2011 ◽  
Vol 286 (22) ◽  
pp. 20020-20030 ◽  
Author(s):  
Murilo S. Alves ◽  
Pedro A. B. Reis ◽  
Silvana P. Dadalto ◽  
Jerusa A. Q. A. Faria ◽  
Elizabeth P. B. Fontes ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Transcription Factor ◽  
Osmotic Stress ◽  
Er Stress ◽  
Unfolded Protein ◽  
Eukaryotic Organisms ◽  
Protein Response

As in all other eukaryotic organisms, endoplasmic reticulum (ER) stress triggers the evolutionarily conserved unfolded protein response in soybean, but it also communicates with other adaptive signaling responses, such as osmotic stress-induced and ER stress-induced programmed cell death. These two signaling pathways converge at the level of gene transcription to activate an integrated cascade that is mediated by N-rich proteins (NRPs). Here, we describe a novel transcription factor, GmERD15 (Glycine max Early Responsive to Dehydration 15), which is induced by ER stress and osmotic stress to activate the expression of NRP genes. GmERD15 was isolated because of its capacity to stably associate with the NRP-B promoter in yeast. It specifically binds to a 187-bp fragment of the NRP-B promoter in vitro and activates the transcription of a reporter gene in yeast. Furthermore, GmERD15 was found in both the cytoplasm and the nucleus, and a ChIP assay revealed that it binds to the NRP-B promoter in vivo. Expression of GmERD15 in soybean protoplasts activated the NRP-B promoter and induced expression of the NRP-B gene. Collectively, these results support the interpretation that GmERD15 functions as an upstream component of stress-induced NRP-B-mediated signaling to connect stress in the ER to an osmotic stress-induced cell death signal.

scholarly journals The Xenopus laevis U2 gene distal sequence element (enhancer) is composed of four subdomains that can act independently and are partly functionally redundant.

1989 ◽  
Vol 9 (4) ◽  
pp. 1682-1690 ◽  
Author(s):  
G Tebb ◽  
I W Mattaj
Keyword(s):  
Transcription Factor ◽  
Xenopus Oocytes ◽  
Small Nuclear Rna ◽  
Base Pairs ◽  
Sequence Element ◽  
Nuclear Factors ◽  
Nuclear Rna ◽  
The Individual ◽  
Mutant Genes

The sequences involved in enhancement of transcription of the Xenopus U2 small nuclear RNA gene by the distal sequence element (DSE) of its promoter were analyzed in detail by microinjection of mutant genes into Xenopus oocytes. The DSE was shown to be roughly 60 base pairs long. Within this region, four motifs were found to contribute to DSE function: an ATGCAAAT octamer sequence, an SpI binding site, and two additional motifs which, since they are related in sequence, may bind the same transcription factor. These motifs were named D2 (for DSE; U2). Both the octamer sequence and the SpI site bound nuclear factors in vitro, but no factor binding to the D2 motifs was detected. All four elements were independently capable of enhancing transcription of the U2 gene to some extent. Furthermore, when assayed under both competitive and noncompetitive conditions, the individual units of the DSE displayed functional redundancy.

scholarly journals The journey from Two-Step to Multi-Step Phosphorelay Signaling Systems

2021 ◽  
Vol 21 ◽  
Author(s):  
Deepti Singh ◽  
Priyanka Gupta ◽  
Sneh Lata Singla-Pareek ◽  
Kadambot H.M Siddique ◽  
Ashwani Pareek
Keyword(s):  
Response Regulator ◽  
Signal Transmission ◽  
Crop Improvement ◽  
Domain Architecture ◽  
Individual Member ◽  
Signaling Systems ◽  
Structural Modifications ◽  
Phosphorylation Mechanism ◽  
The Individual ◽  
Eukaryotic Organisms

Background: The two-component signaling (TCS) system is an important signal transduction machinery in prokaryotes and eukaryotes, excluding animals, that uses a protein phosphorylation mechanism for signal transmission. Conclusion: Prokaryotes have a primitive type of TCS machinery, which mainly comprises a membrane-bound sensory histidine kinase (HK) and its cognate cytoplasmic response regulator (RR). Hence, it is sometimes referred to as two-step phosphorelay (TSP). Eukaryotes have more sophisticated signaling machinery, with an extra component between HK and RR, being a histidine-containing phosphotransfer (HPT) protein that shuttles between HK and RR to communicate signal baggage. As a result, the TSP has evolved from a two-step phosphorelay (His–Asp) in simple prokaryotes to a multi-step phosphorelay (MSP) cascade (His–Asp–His–Asp) in complex eukaryotic organisms, such as plants, to mediate the signaling network. This molecular evolution is also reflected in the form of considerable structural modifications in the domain architecture of the individual components of the TCS system. In this review, we present the journey of the evolution of the TCS system from the primitive TSP to the advanced MSP across the genera. This information will be highly useful in designing the future strategies of crop improvement based on the individual member of the TCS machinery.

scholarly journals Constructing the Processes of a Person’s Identification and Self-Identification Within a Naturalistic Approach

2020 ◽  
pp. 90-96
Author(s):  
Anna S. Petrakova ◽  
Keyword(s):  
Identity Formation ◽  
Social Environment ◽  
Social Relations ◽  
External World ◽  
Personal Identification ◽  
Naturalistic Approach ◽  
Self Recognition ◽  
Human Need ◽  
The Individual ◽  
Identification Processes

Issues of identity formation affect the essential foundations of human being in the world. The identification processes carried out by a person allow him/her to self-determine in society, to understand his/her own place in the structure of social relations and the purpose of his/her life. To date, science has no unambiguous understanding of the essence of identification. In this regard, this article is aimed at identifying the bases and factors of the processes of identification. In this study, the author mainly used a naturalistic approach to the understanding of the processes of identification, since it offers the basis for identification to consider the individual need of a person for self-determination. Based on the methods of comparative analysis, synthesis, generalization and abstraction, the basic concepts on the problem of identification were compared, the general and the specific in the points of view of various authors were identified, which contributed to a more thorough and detailed study of the phenomenon of identification. Identification is a process of interaction with the external, mainly social environment, during which a person identifies with objects and phenomena of the external world. The basis of identification, as shown by the study of most of the concepts available in science, is the human need for self-recognition. It is this need that initiates the process itself. However, in the course of identification, the sociocultural context plays a crucial role, in which a person recognizes oneself in others by searching for common foundations of being. In turn, selfidentification allows comparing the components of oneself with each other via thought communication. In unity, the processes of identification and self-identification form the identity of a person, both to oneself and to society. Identity initiates behavioral manifestations. In itself, it is unstable, since it is influenced by the external social environment. Identification can occur both for several reasons, and for many. Moreover, the sense of identity can be both actual, based on the analysis of the qualities of objects of the external world and their comparison with their own characteristics, and fictitious, formed as a result of inspiring the individual to be convinced of similarity. In the latter case, we are talking about manipulation. Identity is a prerequisite for the successful socialization of an individual, as it allows not only identifying identity with society, but also realizing its integrity and isolation from it. All this allows a person to function and develop harmoniously. The materials of the article are of practical value, since they can be used as a theoretical and methodological basis for the further development of the problem of personal identification in the framework of sociophilosophical or wider humanitarian research.

scholarly journals Starvation-induced cell fusion and heterokaryosis frequently escape imperfect allorecognition systems in an asexual fungal pathogen

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Vasileios Vangalis ◽  
Ilya Likhotkin ◽  
Michael Knop ◽  
Milton A. Typas ◽  
Ioannis A. Papaioannou
Keyword(s):  
Cell Fate ◽  
Cell Fusion ◽  
Evolutionary Dynamics ◽  
Genetic Recombination ◽  
Genetic Material ◽  
Protective Function ◽  
Parasexual Cycle ◽  
Somatic Incompatibility ◽  
Self Recognition ◽  
Different Strains

Abstract Background Asexual fungi include important pathogens of plants and other organisms, and their effective management requires understanding of their evolutionary dynamics. Genetic recombination is critical for adaptability and could be achieved via heterokaryosis — the co-existence of genetically different nuclei in a cell resulting from fusion of non-self spores or hyphae — and the parasexual cycle in the absence of sexual reproduction. Fusion between different strains and establishment of viable heterokaryons are believed to be rare due to non-self recognition systems. Here, we investigate the extent and mechanisms of cell fusion and heterokaryosis in the important asexual plant pathogen Verticillium dahliae. Results We used live-cell imaging and genetic complementation assays of tagged V. dahliae strains to analyze the extent of non-self vegetative fusion, heterokaryotic cell fate, and nuclear behavior. An efficient CRISPR/Cas9-mediated system was developed to investigate the involvement of autophagy in heterokaryosis. Under starvation, non-self fusion of germinating spores occurs frequently regardless of the previously assessed vegetative compatibility of the partners. Supposedly “incompatible” fusions often establish viable heterokaryotic cells and mosaic mycelia, where nuclei can engage in fusion or transfer of genetic material. The molecular machinery of autophagy has a protective function against the destruction of “incompatible” heterokaryons. Conclusions We demonstrate an imperfect function of somatic incompatibility systems in V. dahliae. These systems frequently tolerate the establishment of heterokaryons and potentially the initiation of the parasexual cycle even between strains that were previously regarded as “incompatible.”

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