Browse
Submit Data
Databases
API
Help

Dataset Information

24 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The role, interaction and regulation of the velvet regulator VelB in Aspergillus nidulans.

ABSTRACT: The multifunctional regulator VelB physically interacts with other velvet regulators and the resulting complexes govern development and secondary metabolism in the filamentous fungus Aspergillus nidulans. Here, we further characterize VelB's role in governing asexual development and conidiogenesis in A. nidulans. In asexual spore formation, velB deletion strains show reduced number of conidia, and decreased and delayed mRNA accumulation of the key asexual regulatory genes brlA, abaA, and vosA. Overexpression of velB induces a two-fold increase of asexual spore production compared to wild type. Furthermore, the velB deletion mutant exhibits increased conidial germination rates in the presence of glucose, and rapid germination of conidia in the absence of external carbon sources. In vivo immuno-pull-down analyses reveal that VelB primarily interacts with VosA in both asexual and sexual spores, and VelB and VosA play an inter-dependent role in spore viability, focal trehalose biogenesis and control of conidial germination. Genetic and in vitro studies reveal that AbaA positively regulates velB and vosA mRNA expression during sporogenesis, and directly binds to the promoters of velB and vosA. In summary, VelB acts as a positive regulator of asexual development and regulates spore maturation, focal trehalose biogenesis and germination by interacting with VosA in A. nidulans.

SUBMITTER: Park HS

PROVIDER: S-EPMC3457981 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

The role of VosA/VelB-activated developmental gene vadA in Aspergillus nidulans.

Project description:The filamentous fungus Aspergillus nidulans primarily reproduces by forming asexual spores called conidia, the integrity of which is governed by the NF-?B type velvet regulators VosA and VelB. The VosA-VelB hetero-complex regulates the expression of spore-specific structural and regulatory genes during conidiogenesis. Here, we characterize one of the VosA/VelB-activated developmental genes, called vadA, the expression of which in conidia requires activity of both VosA and VelB. VadA (AN5709) is predicted to be a 532-amino acid length fungal-specific protein with a highly conserved domain of unknown function (DUF) at the N-terminus. This DUF was found to be conserved in many Ascomycota and some Glomeromycota species, suggesting a potential evolutionarily conserved function of this domain in fungi. Deletion studies of vadA indicate that VadA is required for proper downregulation of brlA, fksA, and rodA, and for proper expression of tpsA and orlA during sporogenesis. Moreover, vadA null mutant conidia exhibit decreased trehalose content, but increased ?(1,3)-glucan levels, lower viability, and reduced tolerance to oxidative stress. We further demonstrate that the vadA null mutant shows increased production of the mycotoxin sterigmatocystin. In summary, VadA is a dual-function novel regulator that controls development and secondary metabolism, and participates in bridging differentiation and viability of newly formed conidia in A. nidulans.

| S-EPMC5421774 | biostudies-literature

The velvet Regulator VosA Governs Survival and Secondary Metabolism of Sexual Spores in Aspergillus nidulans.

Project description:The velvet regulator VosA plays a pivotal role in asexual sporulation in the model filamentous fungus Aspergillus nidulans. In the present study, we characterize the roles of VosA in sexual spores (ascospores) in A. nidulans. During ascospore maturation, the deletion of vosA causes a rapid decrease in spore viability. The absence of vosA also results in a lack of trehalose biogenesis and decreased tolerance of ascospores to thermal and oxidative stresses. RNA-seq-based genome-wide expression analysis demonstrated that the loss of vosA leads to elevated expression of sterigmatocystin (ST) biosynthetic genes and a slight increase in ST production in ascospores. Moreover, the deletion of vosA causes upregulation of additional gene clusters associated with the biosynthesis of other secondary metabolites, including asperthecin, microperfuranone, and monodictyphenone. On the other hand, the lack of vosA results in the downregulation of various genes involved in primary metabolism. In addition, vosA deletion alters mRNA levels of genes associated with the cell wall integrity and trehalose biosynthesis. Overall, these results demonstrate that the velvet regulator VosA plays a key role in the maturation and the cellular and metabolic integrity of sexual spores in A. nidulans.

| S-EPMC7016683 | biostudies-literature

Velvet activated McrA plays a key role in cellular and metabolic development in Aspergillus nidulans.

Project description:McrA is a key transcription factor that functions as a global repressor of fungal secondary metabolism in Aspergillus species. Here, we report that mcrA is one of the VosA-VelB target genes and McrA governs the cellular and metabolic development in Aspergillus nidulans. The deletion of mcrA resulted in a reduced number of conidia and decreased mRNA levels of brlA, the key asexual developmental activator. In addition, the absence of mcrA led to a loss of long-term viability of asexual spores (conidia), which is likely associated with the lack of conidial trehalose and increased β-(1,3)-glucan levels in conidia. In supporting its repressive role, the mcrA deletion mutant conidia contain more amounts of sterigmatocystin and an unknown metabolite than the wild type conidia. While overexpression of mcrA caused the fluffy-autolytic phenotype coupled with accelerated cell death, deletion of mcrA did not fully suppress the developmental defects caused by the lack of the regulator of G-protein signaling protein FlbA. On the contrary to the cellular development, sterigmatocystin production was restored in the ΔflbA ΔmcrA double mutant, and overexpression of mcrA completely blocked the production of sterigmatocystin. Overall, McrA plays a multiple role in governing growth, development, spore viability, and secondary metabolism in A. nidulans.

| S-EPMC7493923 | biostudies-literature

Velvet-mediated repression of ?-glucan synthesis in Aspergillus nidulans spores.

Project description:Beta-glucans are a heterologous group of fibrous glucose polymers that are a major constituent of cell walls in Ascomycetes and Basidiomycetes fungi. Synthesis of ? (1,3)- and (1,6)-glucans is coordinated with fungal cell growth and development, thus, is under tight genetic regulation. Here, we report that ?-glucan synthesis in both asexual and sexual spores is turned off by the NF-kB like fungal regulators VosA and VelB in Aspergillus nidulans. Our genetic and genomic analyses have revealed that both VosA and VelB are necessary for proper down-regulation of cell wall biosynthetic genes including those associated with ?-glucan synthesis in both types of spores. The deletion of vosA or velB results in elevated accumulation of ?-glucan in asexual spores. Double mutant analyses indicate that VosA and VelB play an inter-dependent role in repressing ?-glucan synthesis in asexual spores. In vivo chromatin immuno-precipitation analysis shows that both VelB and VosA bind to the promoter region of the ?-glucan synthase gene fksA in asexual spores. Similarly, VosA is required for proper repression of ?-glucan synthesis in sexual spores. In summary, the VosA-VelB hetero-complex is a key regulatory unit tightly controlling proper levels of ?-glucan synthesis in asexual and sexual spores.

| S-EPMC4426670 | biostudies-literature

Suppressor mutagenesis identifies a velvet complex remediator of Aspergillus nidulans secondary metabolism.

Project description:Fungal secondary metabolites (SM) are bioactive compounds that are important in fungal ecology and, moreover, both harmful and useful in human endeavors (e.g., as toxins and pharmaceuticals). Recently a nuclear heterocomplex termed the Velvet complex, characterized in the model ascomycete Aspergillus nidulans, was found to be critical for SM production. Deletion of two members of the Velvet complex, laeA and veA, results in near loss of SM and defective sexual spore production in A. nidulans and other species. Using a multicopy-suppressor genetics approach, we have isolated an Aspergillus nidulans gene named rsmA (remediation of secondary metabolism) based upon its ability to remediate secondary metabolism in ?laeA and ?veA backgrounds. Overexpression of rsmA (OE::rsmA) restores production of sterigmatocystin (ST) (a carcinogenic SM) via transcriptional activation of ST biosynthetic genes. However, defects in sexual reproduction in either ?laeA or ?veA strains cannot be overcome by OE::rsmA. An intact Velvet complex coupled with an OE::rsmA allele increases SM many fold over the wild-type level, but loss of rsmA does not decrease SM. RsmA encodes a putative bZIP basic leucine zipper-type transcription factor.

| S-EPMC3008278 | biostudies-literature

Unveiling the Functions of the VosA-VelB Target Gene <i>vidD</i> in <i>Aspergillus nidulans</i>.

Project description:The velvet regulators VosA and VelB are primarily involved in spore maturation and dormancy. Previous studies found that the VosA-VelB hetero-complex coordinates certain target genes that are related to fungal differentiation and conidial maturation in Aspergillus nidulans. Here, we characterized the VosA/VelB-inhibited developmental gene vidD in A. nidulans. Phenotypic analyses demonstrated that the vidD deleted mutant exhibited defect fungal growth, a reduced number of conidia, and delayed formation of sexual fruiting bodies. The deletion of vidD decreased the amount of conidial trehalose, increased the sensitivity against heat stress, and reduced the conidial viability. Moreover, the absence of vidD resulted in increased production of sterigmatocystin. Together, these results show that VidD is required for proper fungal growth, development, and sterigmatocystin production in A. nidulans.

| S-EPMC8259823 | biostudies-literature

Interaction of Aspergillus nidulans and Streptomyces rapamycinicus

Project description:Gene expression analysis of four different treatments of Aspergillus nidulans. reference line (A.nidulans), line A (A.nidulans + Streptomyces rapamycinicus), line B (A.nidulans + orsellinic acid), line C (A.nidulans + lecanoric acid)

2011-05-25 | GSE25266 | GEO

Interaction of Aspergillus nidulans and Streptomyces rapamycinicus

2011-05-25 | E-GEOD-25266 | biostudies-arrayexpress

A novel regulator couples sporogenesis and trehalose biogenesis in Aspergillus nidulans.

Project description:Trehalose is a compatible osmolyte produced by bacteria, fungi, insects and plants to protect the integrity of cells against various environmental stresses. Spores, the reproductive, survival and infection bodies of fungi require high amounts of trehalose for long-term survival. Here, via a gain-of-function genetic screen, we identify the novel regulator VosA that couples the formation of spores and focal trehalose biogenesis in the model fungus Aspergillus nidulans. The vosA gene is expressed specifically during the formation of both sexual and asexual spores (conidia). Levels of vosA mRNA and protein are high in both types of spore. The deletion of vosA results in the lack of trehalose in spores, a rapid loss of the cytoplasm, organelles and viability of spores, and a dramatic reduction in tolerance of conidia to heat and oxidative stress. Moreover, the absence of vosA causes uncontrolled activation of asexual development, whereas the enhanced expression of vosA blocks sporulation, suggesting that VosA also functions in negative-feedback regulation of sporogenesis. VosA localizes in the nucleus of mature conidia and its C-terminal region contains a potential transcription activation domain, indicating that it may function as a transcription factor primarily controlling the late process of sporulation including trehalose biogenesis. VosA is conserved in most fungi and may define a new fungus-specific transcription factor family.

| S-EPMC1978537 | biostudies-literature

Crosstalk between Three Fungus-specific Transcription Factors, WetA, VosA, and VelB, in Asexual Spores of Aspergillus nidulans

Project description:This SuperSeries is composed of the SubSeries listed below.

2021-01-11 | GSE154640 | GEO