Genetic basis for coordination of meiosis and sexual structure maturation in Cryptococcus neoformans
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ABSTRACT:
ORGANISM(S): Cryptococcus neoformans var. neoformans XL280
PROVIDER: GSE111975 | GEO | 2018/11/14
REPOSITORIES: GEO
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Project description:Ray2013 - Meiotic initiation in S. cerevisiae
A mathematical representation of early meiotic events, particularly feedback mechanisms at the system level and phosphorylation of signalling molecules for regulating protein activities, is described here
This model is described in the article:
Dynamic modeling of yeast meiotic initiation.
Ray D, Su Y, Ye P.
BMC Syst Biol. 2013 May 1;7:37
Abstract:
BACKGROUND:
Meiosis is the sexual reproduction process common to eukaryotes. The diploid yeast Saccharomyces cerevisiae undergoes meiosis in sporulation medium to form four haploid spores. Initiation of the process is tightly controlled by intricate networks of positive and negative feedback loops. Intriguingly, expression of early meiotic proteins occurs within a narrow time window. Further, sporulation efficiency is strikingly different for yeast strains with distinct mutations or genetic backgrounds. To investigate signal transduction pathways that regulate transient protein expression and sporulation efficiency, we develop a mathematical model using ordinary differential equations. The model describes early meiotic events, particularly feedback mechanisms at the system level and phosphorylation of signaling molecules for regulating protein activities.
RESULTS:
The mathematical model is capable of simulating the orderly and transient dynamics of meiotic proteins including Ime1, the master regulator of meiotic initiation, and Ime2, a kinase encoded by an early gene. The model is validated by quantitative sporulation phenotypes of single-gene knockouts. Thus, we can use the model to make novel predictions on the cooperation between proteins in the signaling pathway. Virtual perturbations on feedback loops suggest that both positive and negative feedback loops are required to terminate expression of early meiotic proteins. Bifurcation analyses on feedback loops indicate that multiple feedback loops are coordinated to modulate sporulation efficiency. In particular, positive auto-regulation of Ime2 produces a bistable system with a normal meiotic state and a more efficient meiotic state.
CONCLUSIONS:
By systematically scanning through feedback loops in the mathematical model, we demonstrate that, in yeast, the decisions to terminate protein expression and to sporulate at different efficiencies stem from feedback signals toward the master regulator Ime1 and the early meiotic protein Ime2. We argue that the architecture of meiotic initiation pathway generates a robust mechanism that assures a rapid and complete transition into meiosis. This type of systems-level regulation is a commonly used mechanism controlling developmental programs in yeast and other organisms. Our mathematical model uncovers key regulations that can be manipulated to enhance sporulation efficiency, an important first step in the development of new strategies for producing gametes with high quality and quantity.
This model is hosted on BioModels Database
and identified
by: BIOMD0000000626
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource
for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to the public
domain worldwide. Please refer to CC0 Public Domain
Dedication
for more information.
2017-02-03 | BIOMD0000000626 | BioModels
Project description:Study of the meiotic transcriptional profile of transcription factor mutants. The transcription factors atf21 and atf31 are highly induced during the meiotic divisions and required for proper spore formation. To identify possible targets of these transcription factors we compared the transcriptional profile of atf21 and atf31 mutants with that of wild type cells undergoing meiosis. We used haploid h90 cells for this experiment. Removal of nitrogen from the medium induces mating to form diploids, which immediately undergo meiosis and sporulation. This type of meiosis is not very synchronous. This experiment is part of a series, E-SNGR-2 to E-SNGR-7.
2002-08-05 | E-SNGR-4 | biostudies-arrayexpress
Project description:Sexual reproduction facilitates infection by the production of both a lineage advantage and infectious sexual spores in the ubiquitous human fungal pathogen Cryptococcus deneoformans. However, the regulatory determinants specific for initiating mating remain poorly understood. Here, we identified a velvet family regulator, Cva1, that strongly promotes sexual reproduction in C. deneoformans. This regulation was determined to be specific, based on a comprehensive phenotypic analysis of cva1 under 25 distinct in vitro and in vivo growth conditions. We further revealed that Cva1 plays a critical role in the initiation of early mating events, especially sexual cell-cell fusion, but is not important for the late sexual development stages or meiosis. Thus, Cva1 specifically contributes to mating activation. Importantly, a novel mating-responsive surface protein, Cfs1, serves as the key target of Cva1 during mating, since its absence nearly blocks cell-cell fusion in C. deneoformans and its sister species C. neoformans. Together, our findings provide insight into how C. deneoformans ensures regulatory specificity of mating.
2022-02-10 | GSE196267 | GEO
Project description:Ray2013 - S.cerevisiae meiosis-specific metabolic network
Meiosis is a strongly concerved cell division program that generates haploid gametes from a diploid parental cell. Successful meiosis is the fundamental basis of sexual reproduction. Multiple lines of evidence suggest a tight link between meiosis and metabolism. Here, yeast meiosis is studied to elucidate the link between reproduction and metabolism. Network flux is obtained using GLPK (GNU Linear Programming Kit) supported by the COBRA Toolbox for Matlab.
This model is described in the article:
Characterization of the metabolic requirements in yeast meiosis.
Ray D, Ye P.
PLoS One. 2013 May 8;8(5):e63707.
Abstract:
The diploid yeast Saccharomyces cerevisiae undergoes mitosis in glucose-rich medium but enters meiosis in acetate sporulation medium. The transition from mitosis to meiosis involves a remarkable adaptation of the metabolic machinery to the changing environment to meet new energy and biosynthesis requirements. Biochemical studies indicate that five metabolic pathways are active at different stages of sporulation: glutamate formation, tricarboxylic acid cycle, glyoxylate cycle, gluconeogenesis, and glycogenolysis. A dynamic synthesis of macromolecules, including nucleotides, amino acids, and lipids, is also observed. However, the metabolic requirements of sporulating cells are poorly understood. In this study, we apply flux balance analyses to uncover optimal principles driving the operation of metabolic networks over the entire period of sporulation. A meiosis-specific metabolic network is constructed, and flux distribution is simulated using ten objective functions combined with time-course expression-based reaction constraints. By systematically evaluating the correlation between computational and experimental fluxes on pathways and macromolecule syntheses, the metabolic requirements of cells are determined: sporulation requires maximization of ATP production and macromolecule syntheses in the early phase followed by maximization of carbohydrate breakdown and minimization of ATP production in the middle and late stages. Our computational models are validated by in silico deletion of enzymes known to be essential for sporulation. Finally, the models are used to predict novel metabolic genes required for sporulation. This study indicates that yeast cells have distinct metabolic requirements at different phases of meiosis, which may reflect regulation that realizes the optimal outcome of sporulation. Our meiosis-specific network models provide a framework for an in-depth understanding of the roles of enzymes and reactions, and may open new avenues for engineering metabolic pathways to improve sporulation efficiency.
This model is hosted on BioModels Database
and identified
by: MODEL1303140001
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource
for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to the public
domain worldwide. Please refer to CC0 Public Domain
Dedication
for more information.
2005-01-01 | MODEL1303140001 | BioModels
Project description:This study newly identified Tripelennamine (TA) as an inhibitor of yeast meiosis and sporulation. To examine if and how exposure of sporulating yeast cells to TA changes the meiotic transcriptional program cells were sporulated for 0, 4, and 8 hours in the presence or absence of 100 uM TA.
2010-03-31 | E-MEXP-2522 | biostudies-arrayexpress
Project description:Meiosis was compared in msh5-22 and wild type strains of C. cinerea at 6 time points spanning the meiotic timecourse. Abstract: The basidiomycete Coprinopsis cinerea is well-suited to studies of meiosis because meiosis progresses synchronously in ten million cells within each mushroom cap. Approximately 20% of C. cinerea genes exhibit changing expression during meiosis, but meiosis and mushroom development happen concurrently so differentially expressed genes might not be directly involved in meiotic processes. Using microarrays, we examined global gene expression across a meiotic time course in two mutants in which meiosis arrests but mushrooms develop normally. Genes differentially expressed in the mutants compared to wild type are likely to be involved in meiosis and sporulation as opposed to mushroom development. In rad50-1, which arrests in late prophase, RNA abundance for a group of early meiotic genes remains high, while the expression of a group of late meiotic genes is never induced. In contrast, in msh5-22 (which fails to undergo pre-meiotic DNA replication), both early and late meiotic genes are underexpressed relative to wild type at late meiotic time points as the cells die. Genes that are differentially expressed in both mutants are particularly strong candidates for playing roles in meiosis and sporulation.
2012-05-15 | GSE37943 | GEO
Project description:Meiosis was compared in rad50-1 and wild type strains of C. cinerea at 6 time points spanning the meiotic timecourse. Abstract: The basidiomycete Coprinopsis cinerea is well-suited to studies of meiosis because meiosis progresses synchronously in ten million cells within each mushroom cap. Approximately 20% of C. cinerea genes exhibit changing expression during meiosis, but meiosis and mushroom development happen concurrently so differentially expressed genes might not be directly involved in meiotic processes. Using microarrays, we examined global gene expression across a meiotic time course in two mutants in which meiosis arrests but mushrooms develop normally. Genes differentially expressed in the mutants compared to wild type are likely to be involved in meiosis and sporulation as opposed to mushroom development. In rad50-1, which arrests in late prophase, RNA abundance for a group of early meiotic genes remains high, while the expression of a group of late meiotic genes is never induced. In contrast, in msh5-22 (which fails to undergo pre-meiotic DNA replication), both early and late meiotic genes are underexpressed relative to wild type at late meiotic time points as the cells die. Genes that are differentially expressed in both mutants are particularly strong candidates for playing roles in meiosis and sporulation.
2012-05-15 | GSE37942 | GEO
Project description:Inactivation of the yeast IME4 gene, the yeast homologue of METTL3, was shown to result in the loss of m6A in mRNA of mutant cells grown in sporulation medium. We attempted to characterize the effects of ime4 deletion on gene expression under vegetative and meiosis-inducing conditions. The results show that in vegetatively-growing ime4-/- cells there is an increased expression of the RME1 gene (repressor of meiosis) which prevents precocious entry into the meiotic program. Mutant yeast cells showed reduced expression levels of genes involved in ribosome biogenesis and gene expression processes. Surprisingly, despite the fact that a diploid strain was analyzed, there was also a striking change in the expression level of haploid-specific genes, suggesting that RNA methylation may be used to enforce the sexual identity of diploid cells, required for the implementation of the gametogenesis program. Consistently, when cells were induced to undergo meiosis, ime4-/- diploids failed to undergo the meiotic divisions. Among the genes showing reduced expression in the mutant were IME1 and IME2, the two known inducers of meiosis. Thus, the yeast IME4 gene plays an important role in the regulation of the developmental switch from vegetative cells into gametogenesis. WT and ime4 -/- yeast cells were grown vegetatively in YPD (Yeast extract, Peptone, Dextrose) medium, and transferred to sporulation medium(1% Kacetate) for induction of sporulation for 4 hrs. RNA was purified from the cells and hybridized to Affymetrix microarrays. Experiments were conducted in biological replicates.
2012-04-24 | E-GEOD-36958 | biostudies-arrayexpress
Project description:Meiotic recombination hotspots are associated with histone post-translational modifications and open chromatin. However, it remains unclear how histone modifications and chromatin structure directly regulate meiotic recombination. Here, we identify acetylation of histone H4 at Lys44 (H4K44ac) as a new histone modification, occurring on the nucleosomal lateral surface. We show that H4K44ac is specific to yeast sporulation, rising during yeast meiosis and displaying genome-wide enrichment at recombination hotspots in meiosis. The H4K44 residue is required for normal meiotic recombination, for normal levels of double strand breaks during meiosis, and for optimal sporulation. Non-modifiable substitution H4K44R results in reduced MNase digestion and decreased binding of recombination-associated proteins at hotspots. Our results show that H4K44ac creates an accessible chromatin environment for key proteins to facilitate meiotic recombination.
2015-12-07 | GSE59003 | GEO
Project description:Meiotic recombination hotspots are associated with histone post-translational modifications and open chromatin. However, it remains unclear how histone modifications and chromatin structure directly regulate meiotic recombination. Here, we identify acetylation of histone H4 at Lys44 (H4K44ac) as a new histone modification, occurring on the nucleosomal lateral surface. We show that H4K44ac is specific to yeast sporulation, rising during yeast meiosis and displaying genome-wide enrichment at recombination hotspots in meiosis. The H4K44 residue is required for normal meiotic recombination, for normal levels of double strand breaks during meiosis, and for optimal sporulation. Non-modifiable substitution H4K44R results in reduced MNase digestion and decreased binding of recombination-associated proteins at hotspots. Our results show that H4K44ac creates an accessible chromatin environment for key proteins to facilitate meiotic recombination.
2015-12-07 | GSE59004 | GEO