Genetic Networks That Govern Sexual Reproduction in the Pezizomycotina

2021 ◽  
Author(s):  
Andi M. Wilson ◽  
P. Markus Wilken ◽  
Michael J. Wingfield ◽  
Brenda D. Wingfield
Keyword(s):  
Transcription Factors ◽  
Sexual Reproduction ◽  
Filamentous Fungi ◽  
Sexual Development ◽  
Genetic Networks ◽  
Sexual Cycle ◽  
Precise Control ◽  
Master Regulators ◽  
Expression Of Genes ◽  
Complex Process

Sexual development in filamentous fungi is a complex process that relies on the precise control of and interaction between a variety of genetic networks and pathways. The mating-type ( MAT ) genes are the master regulators of this process and typically act as transcription factors, which control the expression of genes involved all stages of the sexual cycle.

scholarly journals The Expression of Sterigmatocystin and Penicillin Genes in Aspergillus nidulans Is Controlled by veA, a Gene Required for Sexual Development

2003 ◽  
Vol 2 (6) ◽  
pp. 1178-1186 ◽  
Author(s):  
Naoki Kato ◽  
Wilhelmina Brooks ◽  
Ana M. Calvo
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Secondary Metabolism ◽  
Aspergillus Nidulans ◽  
Sexual Development ◽  
Morphological Development ◽  
Penicillin Biosynthesis ◽  
Penicillin Production ◽  
Expression Of Genes ◽  
Penicillin Genes

ABSTRACT Secondary metabolism is commonly associated with morphological development in microorganisms, including fungi. We found that veA, a gene previously shown to control the Aspergillus nidulans sexual/asexual developmental ratio in response to light, also controls secondary metabolism. Specifically, veA regulates the expression of genes implicated in the synthesis of the mycotoxin sterigmatocystin and the antibiotic penicillin. veA is necessary for the expression of the transcription factor aflR, which activates the gene cluster that leads to the production of sterigmatocystin. veA is also necessary for penicillin production. Our results indicated that although veA represses the transcription of the isopenicillin synthetase gene ipnA, it is necessary for the expression of acvA, the key gene in the first step of penicillin biosynthesis, encoding the delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine synthetase. With respect to the mechanism of veA in directing morphological development, veA has little effect on the expression of the known sexual transcription factors nsdD and steA. However, we found that veA regulates the expression of the asexual transcription factor brlA by modulating the α/β transcript ratio that controls conidiation.

scholarly journals Intestinal delta-6-desaturase activity determines host range for Toxoplasma sexual reproduction

2019 ◽  
Author(s):  
Bruno Martorelli Di Genova ◽  
Sarah K. Wilson ◽  
J.P. Dubey ◽  
Laura J. Knoll
Keyword(s):  
Linoleic Acid ◽  
Sexual Reproduction ◽  
Sexual Development ◽  
Desaturase Activity ◽  
Companion Animals ◽  
Species Specificity ◽  
Sexual Cycle ◽  
Species Barrier ◽  
Eukaryotic Microbes ◽  
Delta 6 Desaturase

AbstractMany eukaryotic microbes have complex lifecycles that include both sexual and asexual phases with strict species-specificity. While the asexual cycle of the protistan parasite Toxoplasma gondii can occur in any warm-blooded mammal, the sexual cycle is restricted to the feline intestine1. The molecular determinants that identify cats as the definitive host for T. gondii are unknown. Here, we defined the mechanism of species specificity for T. gondii sexual development and break the species barrier to allow the sexual cycle to occur in mice. We determined that T. gondii sexual development occurs when cultured feline intestinal epithelial cells are supplemented with linoleic acid. Felines are the only mammals that lack delta-6-desaturase activity in their intestines, which is required for linoleic acid metabolism, resulting in systemic excess of linoleic acid2, 3. We found that inhibition of murine delta-6-desaturase and supplementation of their diet with linoleic acid allowed T. gondii sexual development in mice. This mechanism of species specificity is the first defined for a parasite sexual cycle. This work highlights how host diet and metabolism shape coevolution with microbes. The key to unlocking the species boundaries for other eukaryotic microbes may also rely on the lipid composition of their environments as we see increasing evidence for the importance of host lipid metabolism during parasitic lifecycles4, 5. Pregnant women are advised against handling cat litter as maternal infection with T. gondii can be transmitted to the fetus with potentially lethal outcomes. Knowing the molecular components that create a conducive environment for T. gondii sexual reproduction will allow for development of therapeutics that prevent shedding of T. gondii parasites. Finally, given the current reliance on companion animals to study T. gondii sexual development, this work will allow the T. gondii field to use of alternative models in future studies.

The Role of Retinoblastoma Protein in Cell Cycle Regulation: An Updated Review

2021 ◽  
Vol 20 ◽  
Author(s):  
Rabih Roufayel ◽  
Rabih Mezher ◽  
Kenneth B. Storey
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Transcription Factors ◽  
Cell Cycle Control ◽  
Expression Of Genes ◽  
E2f Transcription Factor ◽  
Cellular Energetics ◽  
Development And Differentiation ◽  
E2f Transcription Factors ◽  
Rb Phosphorylation

: Selected transcription factors have critical roles to play in organism survival by regulating the expression of genes that control the adaptations needed to handle stress conditions. The retinoblastoma (Rb) protein coupled with the E2F transcription factor family was demonstrated to have roles in controlling the cell cycle during freezing and associated environmental stresses (anoxia, dehydration). Rb phosphorylation or acetylation at different sites provide a mechanism for repressing cell proliferation that is under the control of E2F transcription factors in animals facing stresses that disrupt cellular energetics or cell volume controls. Other central regulators of the cell cycle including Cyclins, Cyclin dependent kinases (Cdks), and checkpoint proteins detect DNA damage or any improper replication, blocking further progression of cell cycle and interrupting cell proliferation. This review provides an insight into the molecular regulatory mechanisms of cell cycle control, focusing on Rb-E2F along with Cyclin-Cdk complexes typically involved in development and differentiation that need to be regulated in order to survive extreme cellular stress.

scholarly journals A Synergistic Anti-Diabetic Effect by Ginsenosides Rb1 and Rg3 through Adipogenic and Insulin Signaling Pathways in 3T3-L1 Cells

2021 ◽  
Vol 11 (4) ◽  
pp. 1725
Author(s):  
Hee-Do Hong ◽  
Sun-Il Choi ◽  
Ok-Hwan Lee ◽  
Young-Cheul Kim
Keyword(s):  
Transcription Factors ◽  
Insulin Signaling ◽  
Adipocyte Differentiation ◽  
Red Ginseng ◽  
Inhibitory Effects ◽  
Rt Pcr ◽  
High Concentration ◽  
Expression Of Genes ◽  
The Individual ◽  
Maximal Expression

Although ginsenosides Rb1 and Rg3 have been identified as the significant ginsenosides found in red ginseng that confer anti-diabetic actions, it is unclear whether insulin-sensitizing effects are mediated by the individual compounds or by their combination. To determine the effect of ginsenosides Rb1 and Rg3 on adipocyte differentiation, 3T3-L1 preadipocytes were induced to differentiate the standard hormonal inducers in the absence or presence of ginsenosides Rb1 or Rg3. Additionally, we determined the effects of Rb1, Rg3, or their combination on the expression of genes related to adipocyte differentiation, adipogenic transcription factors, and the insulin signaling pathway in 3T3-L1 cells using semi-quantitative RT-PCR. Rb1 significantly increased the expression of CEBPα, PPARγ, and aP2 mRNAs. However, Rg3 exerted its maximal stimulatory effect on these genes at 1 μM concentration, while a high concentration (50 μM) showed inhibitory effects. Similarly, treatment with Rb1 and Rg3 (1 μM) increased the expression of IRS-1, Akt, PI3K, GLUT4, and adiponectin. Importantly, co-treatment of Rb1 and Rg3 (9:1) induced the maximal expression levels of these mRNAs. Our data indicate that the anti-diabetic activity of red ginseng is, in part, mediated by synergistic actions of Rb1 and Rg3, further supporting the significance of minor Rg3.

scholarly journals HbxB Is a Key Regulator for Stress Response and β-Glucan Biogenesis in Aspergillus nidulans

2021 ◽  
Vol 9 (1) ◽  
pp. 144
Author(s):  
Sung-Hun Son ◽  
Mi-Kyung Lee ◽  
Ye-Eun Son ◽  
Hee-Soo Park
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Aspergillus Nidulans ◽  
Deletion Mutant ◽  
Phenotypic Analysis ◽  
Spore Viability ◽  
Fungal Development ◽  
Expression Of Genes ◽  
Trehalose Biosynthesis

Homeobox transcription factors are conserved in eukaryotes and act as multi-functional transcription factors in filamentous fungi. Previously, it was demonstrated that HbxB governs fungal development and spore viability in Aspergillus nidulans. Here, the role of HbxB in A. nidulans was further characterized. RNA-sequencing revealed that HbxB affects the transcriptomic levels of genes associated with trehalose biosynthesis and response to thermal, oxidative, and radiation stresses in asexual spores called conidia. A phenotypic analysis found that hbxB deletion mutant conidia were more sensitive to ultraviolet stress. The loss of hbxB increased the mRNA expression of genes associated with β-glucan degradation and decreased the amount of β-glucan in conidia. In addition, hbxB deletion affected the expression of the sterigmatocystin gene cluster and the amount of sterigmatocystin. Overall, these results indicated that HbxB is a key transcription factor regulating trehalose biosynthesis, stress tolerance, β-glucan degradation, and sterigmatocystin production in A.nidulans conidia.

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 Parasexuality and Ploidy Change in Candida tropicalis

2013 ◽  
Vol 12 (12) ◽  
pp. 1629-1640 ◽  
Author(s):  
Riyad N. H. Seervai ◽  
Stephen K. Jones ◽  
Matthew P. Hirakawa ◽  
Allison M. Porman ◽  
Richard J. Bennett
Keyword(s):  
Sexual Reproduction ◽  
Candida Tropicalis ◽  
Culture Conditions ◽  
Sexual Cycle ◽  
Chromosome Loss ◽  
Parasexual Cycle ◽  
Content Type ◽  
Ploidy Changes ◽  
Diploid Cells

ABSTRACTCandidaspecies exhibit a variety of ploidy states and modes of sexual reproduction. Most species possess the requisite genes for sexual reproduction, recombination, and meiosis, yet only a few have been reported to undergo a complete sexual cycle including mating and sporulation.Candida albicans, the most studiedCandidaspecies and a prevalent human fungal pathogen, completes its sexual cycle via a parasexual process of concerted chromosome loss rather than a conventional meiosis. In this study, we examine ploidy changes inCandida tropicalis, a closely related species toC. albicansthat was recently revealed to undergo sexual mating.C. tropicalisdiploid cells mate to form tetraploid cells, and we show that these can be induced to undergo chromosome loss to regenerate diploid forms by growth on sorbose medium. The diploid products are themselves mating competent, thereby establishing a parasexual cycle in this species for the first time. Extended incubation (>120 generations) ofC. tropicalistetraploid cells under rich culture conditions also resulted in instability of the tetraploid form and a gradual reduction in ploidy back to the diploid state. The fitness levels ofC. tropicalisdiploid and tetraploid cells were compared, and diploid cells exhibited increased fitness relative to tetraploid cellsin vitro, despite diploid and tetraploid cells having similar doubling times. Collectively, these experiments demonstrate distinct pathways by which a parasexual cycle can occur inC. tropicalisand indicate that nonmeiotic mechanisms drive ploidy changes in this prevalent human pathogen.

Phagocytic specificity during sexual development in Dictyostelium discoideum

1986 ◽  
Vol 32 (2) ◽  
pp. 79-82 ◽  
Author(s):  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Concanavalin A ◽  
Sexual Development ◽  
Wheat Germ ◽  
Giant Cells ◽  
Inhibitory Effect ◽  
Sexual Cycle ◽  
Type I ◽  
Further Development ◽  
Type Receptor

During the sexual cycle of Dictyostelium discoideum, zygote giant cells develop and serve as foci for further development by chemoattracting and cannibalizing hundreds of local amoebae. Previous work has shown that the phagocytic process bears similarities to and differences from asexual endocytosis. In the present study, sexual phagocytosis in D. discoideum was found to be species and developmental stage specific. It was inhibited selectively by glucose and concanavalin A. Although a partial, inhibitory effect of mannose on phagocytosis was not statistically significant, alpha-methylmannosamine, like alpha-methyl-glucose, significantly restored the phagocytic competence of giant cells treated with concanavalin A. Other sugars (N-acetyl glucosamine, N-acetylgalactosamine, and galactose) and lectins (wheat germ agglutinin, Ulex europus type I, and Ricinis communis agglutinin type I) had no significant effect on sexual phagocytosis. Together these data indicate that a glucose-type receptor is involved in selective uptake of D. discoideum amoebae by giant cells.

The rescue of oral development of defective-micronucleate conjugants of Paramecium tetraurelia by normal gametic nuclei

1988 ◽  
Vol 90 (2) ◽  
pp. 287-293
Author(s):  
M. F. CHAU ◽  
STEPHEN F. NG
Keyword(s):  
Sexual Reproduction ◽  
Cell Lines ◽  
Early Stage ◽  
Sexual Cycle ◽  
Paramecium Tetraurelia ◽  
Laser Microbeam ◽  
Nuclear Reorganization ◽  
Oral Development ◽  
Derivatives Of

The present study further analyses the importance of postmeiotic divisional derivatives of the micronucleus in the development of the oral apparatus of Paramecium during sexual reproduction. Cell lines possessing defective micronuclei generated by laser microbeam irradiation of the micronucleus were employed. They exhibited anomalies in nuclear reorganization and stomatogenesis in the sexual cycle. During autogamy, in some cells the micronuclear cycle terminated shortly after meiosis, resulting in the loss of all postmeiotic micronuclear derivatives. Stomatogenesis became arrested at an early stage of assembly of the oral membranelles, but the old oral apparatus was resorbed as usual, leading to the production of astomatous cells at the end of the sexual cycle. Conjugation of these cell lines with normal micronucleates rescued both nucleogenesis and stomatogenesis in the defective micronucleate conjugant, primarily as a result of transfer of the male gametic nucleus from the normal conjugant to the defective-micronucleate mate. These observations demonstrate the stomatogenic significance, in particular in the initiation of oral membranelle assembly, of the gametic nuclei during sexual reproduction. The present study also suggests the possibility of micronuclear activities in the early part of the sexual cycle affecting postzygotic nucleogenesis.

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