scholarly journals The WOPR family protein Ryp1 is a key regulator of gene expression, development, and virulence in the thermally dimorphic fungal pathogen Coccidioides posadasii

2021 ◽  
Author(s):  
Alejandra Mandel ◽  
Sinem Beyhan ◽  
Mark Voorhies ◽  
Lisa F. Shubitz ◽  
John Galgiani ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Fungal Pathogens ◽  
Hyphal Growth ◽  
Outer Wall ◽  
Coccidioides Posadasii ◽  
Family Protein ◽  
Regulated Expression ◽  
Isotropic Expansion ◽  
Mutant Cells

Coccidioides spp. are mammalian fungal pathogens endemic to the southwestern US and other desert regions of Mexico, central and South America, with the bulk of US infections occurring in California and Arizona. In the soil, Coccidioides grows in a hyphal form that differentiates into 3-5 micron asexual spores (arthroconidia). When arthroconidia are inhaled by mammals they undergo a unique developmental transition from polar hyphal growth to isotropic expansion with multiple rounds of nuclear division, prior to segmentation, forming large spherules filled with endospores. Very little is understood about the molecular basis of spherule formation. Here we characterize the role of the conserved transcription factor Ryp1 in Coccidioides development. We show that Coccidioides Δryp1 mutants have altered colony morphology under hypha-promoting conditions and are unable to form mature spherules under spherule-promoting conditions. We analyze the transcriptional profile of wild-type and Δryp1 mutant cells under hypha- and spherule-promoting conditions, thereby defining a set of hypha- or spherule-enriched transcripts (“morphology-regulated” genes) that are dependent on Ryp1 for their expression. Forty percent of morphology-regulated expression is Ryp1-dependent, indicating that Ryp1 plays a dual role in both hyphal and spherule development. Ryp1-dependent transcripts include key virulence factors such as SOWgp, which encodes the spherule outer wall glycoprotein. Concordant with its role in spherule development, we find that the ?ryp1 mutant is completely avirulent in the mouse model of coccidioidomycosis, indicating that Ryp1-dependent pathways are essential for the ability of Coccidioides to cause disease. Vaccination of C57BL/6 mice with live Δryp1 spores does not provide any protection from lethal C. posadasii intranasal infection, consistent with our findings that the Δryp1 mutant fails to make mature spherules and likely does not express key antigens required for effective vaccination. Taken together, this work identifies the first transcription factor that drives mature spherulation and virulence in Coccidioides.

scholarly journals Myosin-V, Kinesin-1, and Kinesin-3 Cooperate in Hyphal Growth of the FungusUstilago maydis

2005 ◽  
Vol 16 (11) ◽  
pp. 5191-5201 ◽  
Author(s):  
Isabel Schuchardt ◽  
Daniela Aßmann ◽  
Eckhard Thines ◽  
Christian Schuberth ◽  
Gero Steinberg
Keyword(s):  
Fluorescent Protein ◽  
Hyphal Growth ◽  
Myosin V ◽  
Long Distance ◽  
Long Distance Transport ◽  
Conventional Kinesin ◽  
Green Fluorescent ◽  
Mutant Cells ◽  
Distance Transport

Long-distance transport is crucial for polar-growing cells, such as neurons and fungal hyphae. Kinesins and myosins participate in this process, but their functional interplay is poorly understood. Here, we investigate the role of kinesin motors in hyphal growth of the plant pathogen Ustilago maydis. Although the microtubule plus-ends are directed to the hyphal tip, of all 10 kinesins analyzed, only conventional kinesin (Kinesin-1) and Unc104/Kif1A-like kinesin (Kinesin-3) were up-regulated in hyphae and they are essential for extended hyphal growth. Δkin1 and Δkin3 mutant hyphae grew irregular and remained short, but they were still able to grow polarized. No additional phenotype was detected in Δkin1rkin3 double mutants, but polarity was lost in Δmyo5rkin1 and Δmyo5rkin3 mutant cells, suggesting that kinesins and class V myosin cooperate in hyphal growth. Consistent with such a role in secretion, fusion proteins of green fluorescent protein and Kinesin-1, Myosin-V, and Kinesin-3 accumulate in the apex of hyphae, a region where secretory vesicles cluster to form the fungal Spitzenkörper. Quantitative assays revealed a role of Kin3 in secretion of acid phosphatase, whereas Kin1 was not involved. Our data demonstrate that just two kinesins and at least one myosin support hyphal growth.

scholarly journals SUN-Family Protein UvSUN1 Regulates the Development and Virulence of Ustilaginoidea virens

2021 ◽  
Vol 12 ◽  
Author(s):  
Mina Yu ◽  
Junjie Yu ◽  
Huijuan Cao ◽  
Tianqiao Song ◽  
Xiayan Pan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Hyphal Growth ◽  
Cell Wall Integrity ◽  
Signal Recognition ◽  
Phenotypic Analysis ◽  
Ustilaginoidea Virens ◽  
Group I ◽  
Family Protein ◽  
False Smut

Ustilaginoidea virens, the causal agent of rice false smut disease, is an important plant pathogen that causes severe quantitative and qualitative losses in rice worldwide. UvSUN1 is the only member of Group-I SUN family proteins in U. virens. In this work, the role of UvSUN1 in different aspects of the U. virens biology was studied by phenotypic analysis of Uvsun1 knockout strains. We identified that UvSUN1 was expressed during both conidial germination and the infection of rice. Disruption of the Uvsun1 gene affected the hyphal growth, conidiation, morphology of hyphae and conidia, adhesion and virulence. We also found that UvSUN1 is involved in the production of toxic compounds, which are able to inhibit elongation of the germinated seeds. Moreover, RNA-seq data showed that knockout of Uvsun1 resulted in misregulation of a subset of genes involved in signal recognition and transduction system, glycometabolism, cell wall integrity, and secondary metabolism. Collectively, this study reveals that Uvsun1 is required for growth, cell wall integrity and pathogenicity of U. virens, thereby providing new insights into the function of SUN family proteins in the growth and pathogenesis of this pathogen.

scholarly journals Role of Transcription Factor CaNdt80p in Cell Separation, Hyphal Growth, and Virulence in Candida albicans

2010 ◽  
Vol 9 (4) ◽  
pp. 634-644 ◽  
Author(s):  
Adnane Sellam ◽  
Christopher Askew ◽  
Elias Epp ◽  
Faiza Tebbji ◽  
Alaka Mullick ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Cell Separation ◽  
Hyphal Growth ◽  
Functional Domain ◽  
Transcription Factor Family ◽  
Content Type ◽  
Genes Encoding

ABSTRACT The NDT80/PhoG transcription factor family includes ScNdt80p, a key modulator of the progression of meiotic division in Saccharomyces cerevisiae. In Candida albicans, a member of this family, CaNdt80p, modulates azole sensitivity by controlling the expression of ergosterol biosynthesis genes. We previously demonstrated that CaNdt80p promoter targets, in addition to ERG genes, were significantly enriched in genes related to hyphal growth. Here, we report that CaNdt80p is indeed required for hyphal growth in response to different filament-inducing cues and for the proper expression of genes characterizing the filamentous transcriptional program. These include noteworthy genes encoding cell wall components, such as HWP1, ECE1, RBT4, and ALS3. We also show that CaNdt80p is essential for the completion of cell separation through the direct transcriptional regulation of genes encoding the chitinase Cht3p and the cell wall glucosidase Sun41p. Consistent with their hyphal defect, ndt80 mutants are avirulent in a mouse model of systemic candidiasis. Interestingly, based on functional-domain organization, CaNdt80p seems to be a unique regulator characterizing fungi from the CTG clade within the subphylum Saccharomycotina. Therefore, this study revealed a new role of the novel member of the fungal NDT80 transcription factor family as a regulator of cell separation, hyphal growth, and virulence.

scholarly journals Modulation of fungal virulence through CRZ1 regulated F-BAR-dependent actin remodeling and endocytosis in chickpea infecting phytopathogen Ascochyta rabiei

2020 ◽  
Author(s):  
Manisha Sinha ◽  
Ankita Shree ◽  
Kunal Singh ◽  
Kamal Kumar ◽  
Vimlesh Kumar ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Hyphal Growth ◽  
Ascochyta Rabiei ◽  
Membrane Remodeling ◽  
Fungal Virulence ◽  
Bar Domain ◽  
Early Endosomes ◽  
Host Penetration ◽  
Hyphal Tip

AbstractPolarized hyphal growth of filamentous pathogenic fungi is an essential event for host penetration and colonization. The long-range early endosomal trafficking during the hyphal growth is crucial for nutrient uptake, sensing of host-specific cues, and regulation of effector production. Bin1/Amphiphysin/Rvs167 (BAR) domain-containing proteins mediate fundamental cellular processes, including membrane remodeling and endocytosis. Here, we identified an F-BAR domain protein (ArF-BAR) in the necrotrophic fungus Ascochyta rabiei and demonstrate its involvement in endosome-dependent fungal virulence on the host plant, Cicer arietinum. We show that ArF-BAR regulates endocytosis at the hyphal tip, localizes to the early endosomes, and is involved in actin dynamics. Functional studies involving gene knockout and complementation experiments reveal that ArF-BAR is essential for virulence. The loss-of-function of ArF-BAR results in delayed formation of first septa from the hyphal tip, crucial for host penetration and proliferation. ArF-BAR was induced in response to oxidative stress and infection and localized to endocytic vesicles within the fungal hyphae. We also show that ArF-BAR is able to tubulate synthetic liposomes, suggesting the functional role of F-BAR domain in membrane tubule formation in vivo. Further, our studies identified a stress-induced transcription factor, ArCRZ1 (Calcineurin-responsive zinc finger 1) as key regulator for transcriptional reprogramming of ArF-BAR. We propose a model in which ArCRZ1 functions upstream of ArF-BAR to regulate fungal pathogenesis through a mechanism that involves membrane remodeling and actin cytoskeleton regulation.Author summaryBAR-domain superfamily is known to mold amorphous lipid bilayer into defined tubular shapes and critical for endosome formation and trafficking. Although these processes are studied earlier in the context of their structural and biochemical properties, there is limited evidence on the direct role of F-BAR domain proteins in the pathophysiological development of other economically important fungi. Our study assumes functional significance for plant infection as we identified an F-BAR domain-containing protein that is regulated by a distinct transcriptional network. We characterized F-BAR in a necrotrophic fungal pathogen, Ascochyta rabiei that causes the Ascochyta blight (AB) disease in chickpea plants. Additionally, we have also identified a calcium-regulated CRZ1 transcription factor that regulates the transcription of ArF-BAR. Our study will help to understand the complex interplay underlying the endosome formation required for fungal virulence.

scholarly journals Satb2 is required for the regionalization of retrosplenial cortex

2019 ◽  
Vol 27 (5) ◽  
pp. 1604-1617
Author(s):  
Lei Zhang ◽  
Ning-Ning Song ◽  
Qiong Zhang ◽  
Wan-Ying Mei ◽  
Chun-Hui He ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Molecular Mechanism ◽  
Cortical Development ◽  
Retrosplenial Cortex ◽  
Wild Type ◽  
Efferent Projection ◽  
Mutant Cells

Abstract The retrosplenial cortex (Rsp) is a transitional cortex located between the neocortex and archicortex, but the molecular mechanism specifying Rsp from the archicortex remains elusive. We here report that the transcription factor Satb2 is required for specifying Rsp identity during its morphogenesis. In Satb2 CKO mice, the boundary between the Rsp and archicortex [i.e., subiculum (SubC)] disappears as early as E17.5, and Rsp efferent projection is aberrant. Rsp-specific genes are lost, whereas SubC-specific genes are ectopically expressed in Rsp of Satb2 CKO mice. Furthermore, cell-autonomous role of Satb2 in maintaining Rsp neuron identity is revealed by inactivation of Satb2 in Rsp neurons. Finally, Satb2 represses the transcription of Nr4a2. The misexpression of Nr4a2 together with Ctip2 induces expression of SubC-specific genes in wild-type Rsp, and simultaneous knockdown of these two genes in Rsp Satb2-mutant cells prevents their fate transition to SubC identity. Thus, Satb2 serves as a determinant gene in the Rsp regionalization by repressing Nr4a2 and Ctip2 during cortical development.

scholarly journals Cellular and Molecular Basis of Mutant Haemopoietic Transcription Factor GATA1s

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 607-607
Author(s):  
Soady Kelly ◽  
Gaëtan Juban ◽  
Ludovic Lhermitte ◽  
Elena Karkoulia ◽  
John Strouboulis ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Rna Sequencing ◽  
Embryoid Bodies ◽  
Cyclin D3 ◽  
Wild Type ◽  
Partial Differentiation ◽  
Mutant Cells ◽  
Megakaryocyte Differentiation

Abstract Down Syndrome (DS) (Trisomy 21 – T21) is a common constitutional aneuploidy. Neonates and children with DS have a 150-fold increased risk of developing Acute Myeloid Leukaemia (DS-ML), characterized by a differentiation arrest of immature megakaryocyte-erythroid cells. In virtually all DS-ML patients, somatic mutations in the gene encoding the megakaryocyte-erythroid transcription factor GATA1 are acquired during fetal life leading to the production of a N-terminal truncated form of the GATA1 protein (GATA1s). We, and others, have previously shown that this N-terminal domain is necessary to prevent excessive megakaryocytic proliferation. However, the mechanisms by which GATA1, but not GATA1s, restrains megakaryocytes proliferation are unclear. To gain mechanistic insight, we generated knock-in murine ES cell models expressing biotinylated forms of either full length GATA1 or GATA1s protein. We established large scale in vitro differentiation assays to interrogate embryonic-fetal megakaryocyte differentiation (adapted from Nishikii et al., 2008. J Exp Med; 205 (8) : 1917-27; Figure 1) to define the normal megakaryocytic differentiation pathway in GATA1-expressing cells. ES cells were differentiated into embryoid bodies (EB), which were disaggregated at D6 and CD41+c-kit+ cells were cultured on OP9 feeder layers with TPO, IL6 and IL11. Detailed examination of the differentiation kinetics of populations including FACS-sorting of specific populations followed by reculture, showed complex differentiation pathways as wild type cells differentiated into both megakaryocyte and non-megakaryocyte fates. By contrast, GATA1s-expressing cells principally differentiated into megakaryocyte fate. In addition, as immature CD41+ haemopoietic cells differentiate into the megakaryocyte lineage they lose c-kit expression and CD41 expression increases (Figure 2). In the GATA1s-expressing cells compared to GATA1-expressing cells, there is marked accumulation (5 to 10-fold) of a specific immature megakaryocyte CD41++c-kit+ population that is partially blocked in differentiation (Gate R6). Cell cycle analysis shows an increase in cells in S-phase specifically in this population in GATA1s-expressing cells compared to normal cells (44% vs 27%) together with a decrease in apoptosis (5% vs 11%). To determine GATA1s direct and indirect target genes, we performed ChIP-sequencing and RNA-sequencing. RNA-sequencing of GATA1- and GATA1s-expressing CD41+ populations at D12 showed around 4500 differentially expressed genes (at a p-value of 0.05). Given the differences in cell cycle, it is noteworthy that cyclin D3 and cdk6 were expressed 1.7-fold and 1.5-fold higher in GATA1s- expressing cells. Chromatin in cis-regulatory regions of both genes was bound by GATA1 and GATA1s. Chemical inhibition of the Cyclin D3:Cdk4/6 complex reduced proliferation and induced partial differentiation of mutant cells, suggesting a role of this complex in regulating GATA1s-induced proliferation and differentiation inhibition. Knock-down and overexpression experiments to further test the role of Cyclin D:Cdk4/6 complex in both wild-type and mutant cells are in progress. Taken together, these results suggest that GATA1s alters cell cycle at a specific stage in megakaryocyte differentiation causing partial differentiation arrest and that this is mediated by altered expression and function of a Cyclin D3:Cdk4/6 complex. These results may have more general implications of how mutant transcription factors cause differentiation arrest in leukemia. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

scholarly journals A DedA Family Membrane Protein in Indium Extrusion in Rhodanobacter sp. B2A1Ga4

2021 ◽  
Vol 12 ◽  
Author(s):  
Joana B. Caldeira ◽  
Ana Paula Chung ◽  
Ana Paula Piedade ◽  
Paula V. Morais ◽  
Rita Branco
Keyword(s):  
Negative Impact ◽  
High Tech ◽  
Gene Encoding ◽  
High Accumulation ◽  
Native Strain ◽  
Critical Metal ◽  
Family Protein ◽  
Cellular Metabolic Activity ◽  
Mutant Cells

Indium (In) is a critical metal widely used in electronic equipment, and the supply of this precious metal is a major challenge for sustainable development. The use of microorganisms for the recovery of this critical high-tech element has been considered an excellent eco-friendly strategy. The Rhodanobacter sp. B2A1Ga4 strain, highly resistant to In, was studied in order to disclose the bacterial mechanisms closely linked to the ability to cope with this metal. The mutation of the gene encoding for a DedA protein homolog, YqaA, affected drastically the In resistance and the cellular metabolic activity of strain Rhodanobacter sp. B2A1Ga4 in presence of this metal. This indicates that this protein plays an important role in its In resistance phenotype. The negative impact of In might be related to the high accumulation of the metal into the mutant cells showing In concentration up to approximately 4-fold higher than the native strain. In addition, the expression of the yqaA gene in this mutant reverted the bacterial phenotype with a significant decrease of In accumulation levels into the cells and an increase of In resistance. Membrane potential measurements showed similar values for native and mutant cells, suggesting that there was no loss of proton-motive force in the mutant cells. The results from this study suggest a potential role of this DedA family protein as a membrane transporter involved in the In efflux process. The mutant strain also has the potential to be used as a biotool in bioaccumulation strategies, for the recovery of In in biomining activities.

scholarly journals MPN patients harbor recurrent truncating mutations in transcription factor NF-E2

2013 ◽  
Vol 210 (5) ◽  
pp. 1003-1019 ◽  
Author(s):  
Jonas S. Jutzi ◽  
Ruzhica Bogeska ◽  
Gorica Nikoloski ◽  
Corina A. Schmid ◽  
Thalia S. Seeger ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Myeloproliferative Neoplasms ◽  
Leukemic Transformation ◽  
Deletion Mutations ◽  
Insertion And Deletion ◽  
Molecular Etiology ◽  
Mutant Cells ◽  
Proliferative Advantage

The molecular etiology of myeloproliferative neoplasms (MPNs) remains incompletely understood, despite recent advances incurred through the discovery of several different mutations in MPN patients. We have recently described overexpression of the transcription factor NF-E2 in MPN patients and shown that elevated NF-E2 levels in vivo cause an MPN phenotype and predispose to leukemic transformation in transgenic mice. We report the presence of acquired insertion and deletion mutations in the NF-E2 gene in MPN patients. These result in truncated NF-E2 proteins that enhance wild-type (WT) NF-E2 function and cause erythrocytosis and thrombocytosis in a murine model. NF-E2 mutant cells acquire a proliferative advantage, witnessed by clonal dominance over WT NF-E2 cells in MPN patients. Our data underscore the role of increased NF-E2 activity in the pathophysiology of MPNs.

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