RNAi-Related Dicer and Argonaute Proteins Play Critical Roles for Meiocyte Formation, Chromosome-Axes Lengths and Crossover Patterning in the Fungus Sordaria macrospora

RNA interference (RNAi) is a cellular process involving small RNAs that target and regulate complementary RNA transcripts. This phenomenon has well-characterized roles in regulating gene and transposon expression. In addition, Dicer and Argonaute proteins, which are key players of RNAi, also have functions unrelated to gene repression. We show here that in the filamentous Ascomycete Sordaria macrospora, genes encoding the two Dicer (Dcl1 and Dcl2) and the two Argonaute (Sms2 and Qde2) proteins are dispensable for vegetative growth. However, we identified roles for all four proteins in the sexual cycle. Dcl1 and Sms2 are essential for timely and successful ascus/meiocyte formation. During meiosis per se, Dcl1, Dcl2, and Qde2 modulate, more or less severely, chromosome axis length and crossover numbers, patterning and interference. Additionally, Sms2 is necessary both for correct synaptonemal complex formation and loading of the pro-crossover E3 ligase-protein Hei10. Moreover, meiocyte formation, and thus meiotic induction, is completely blocked in the dcl1 dcl2 and dcl1 sms2 null double mutants. These results indicate complex roles of the RNAi machinery during major steps of the meiotic process with newly uncovered roles for chromosomes-axis length modulation and crossover patterning regulation.

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Interplay between Pds5 and Rec8 in regulating chromosome axis length and crossover frequency

Science Advances ◽

10.1126/sciadv.abe7920 ◽

2021 ◽

Vol 7 (11) ◽

pp. eabe7920

Author(s):

Meihui Song ◽

Binyuan Zhai ◽

Xiao Yang ◽

Taicong Tan ◽

Ying Wang ◽

...

Keyword(s):

Recombination Frequency ◽

Crossover Frequency ◽

Wild Type ◽

Protein Levels ◽

Homolog Pairing ◽

Meiotic Chromosomes ◽

Homologous Chromosome Pairing ◽

Axis Length ◽

Chromosome Axis

Meiotic chromosomes have a loop/axis architecture, with axis length determining crossover frequency. Meiosis-specific Pds5 depletion mutants have shorter chromosome axes and lower homologous chromosome pairing and recombination frequency. However, it is poorly understood how Pds5 coordinately regulates these processes. In this study, we show that only ~20% of wild-type level of Pds5 is required for homolog pairing and that higher levels of Pds5 dosage-dependently regulate axis length and crossover frequency. Moderate changes in Pds5 protein levels do not explicitly impair the basic recombination process. Further investigations show that Pds5 does not regulate chromosome axes by altering Rec8 abundance. Conversely, Rec8 regulates chromosome axis length by modulating Pds5. These findings highlight the important role of Pds5 in regulating meiosis and its relationship with Rec8 to regulate chromosome axis length and crossover frequency with implications for evolutionary adaptation.

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Cytoskeleton interactions in the ascus development and sporulation of Sordaria macrospora

Journal of Cell Science ◽

10.1242/jcs.104.3.883 ◽

1993 ◽

Vol 104 (3) ◽

pp. 883-898 ◽

Cited By ~ 1

Author(s):

C. Thompson-Coffe ◽

D. Zickler

Keyword(s):

Spindle Pole ◽

Sordaria Macrospora ◽

Filamentous Ascomycete ◽

Spindle Pole Bodies ◽

Double Label ◽

Butanedione Monoxime ◽

Myosin Interaction ◽

And Migration ◽

Relationship Of ◽

The Relationship

The organization of actin during meiosis and sporulation in the ascus of the filamentous ascomycete Sordaria macrospora was determined by immunofluorescence without removal of the cell wall. Actin is present as a dense cortical network of microfilaments (MF) and plaques, a perinuclear shell of actin in prophase I of meiosis, and a complex array of MF involved in alignment of prespore nuclei and closure of spore cell membranes. The relationship of actin to the previously examined microtubule system of the ascus was determined by double-label immunofluorescence. The cytoskeletal inhibitors nocodazole, cytochalasin D and 2,3-butanedione monoxime were used to examine the roles of actin and myosin in ascus development. Microfilament and microtubule arrays are interdependant; disruption of one network results in abnormalities in the other. Both microfilaments and actin-myosin interaction are required for separation and migration of duplicated spindle pole bodies, septation and sporulation

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PaTrx1 and PaTrx3, Two Cytosolic Thioredoxins of the Filamentous Ascomycete Podospora anserina Involved in Sexual Development and Cell Degeneration

Eukaryotic Cell ◽

10.1128/ec.00083-07 ◽

2007 ◽

Vol 6 (12) ◽

pp. 2323-2331 ◽

Cited By ~ 20

Author(s):

Fabienne Malagnac ◽

Benjamin Klapholz ◽

Philippe Silar

Keyword(s):

Disulfide Bonds ◽

Mapk Pathway ◽

Sulfur Metabolism ◽

Podospora Anserina ◽

Mitogen Activated Protein Kinase ◽

Cell Degeneration ◽

Stress Genes ◽

Filamentous Ascomycete ◽

Genes Encoding ◽

Protein Disulfide Bonds

ABSTRACT In various organisms, thioredoxins are known to be involved in the reduction of protein disulfide bonds and in protecting the cell from oxidative stress. Genes encoding thioredoxins were found by searching the complete genome sequence of the filamentous ascomycete Podospora anserina. Among them, PaTrx1, PaTrx2, and PaTrx3 are predicted to be canonical cytosolic proteins without additional domains. Targeted disruption of PaTrx1, PaTrx2, and PaTrx3 shows that PaTrx1 is the major thioredoxin involved in sulfur metabolism. Deletions have no effect on peroxide resistance; however, data show that either PaTrx1 or PaTrx3 is necessary for sexual reproduction and for the development of the crippled growth cell degeneration (CG), processes that also required the PaMpk1 mitogen-activated protein kinase (MAPK) pathway. Since PaTrx1 PaTrx3 mutants show not an enhancement but rather an impairment in CG, it seems unlikely that PaTrx1 and PaTrx3 thioredoxins participate in the inhibition of this MAPK pathway. Altogether, these results underscore a role for thioredoxins in fungal development.

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Association between genetic variants in genes encoding Argonaute proteins and cancer risk: A meta-analysis

Pathology - Research and Practice ◽

10.1016/j.prp.2020.152906 ◽

2020 ◽

Vol 216 (5) ◽

pp. 152906 ◽

Cited By ~ 1

Author(s):

Zorana Dobrijević ◽

Suzana Matijašević ◽

Dušanka Savić-Pavićević ◽

Goran Brajušković

Keyword(s):

Cancer Risk ◽

Genetic Variants ◽

Meta Analysis ◽

Argonaute Proteins ◽

Genes Encoding

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Mating-Type-Specific and Nonspecific PAK Kinases Play Shared and Divergent Roles in Cryptococcus neoformans

Eukaryotic Cell ◽

10.1128/ec.1.2.257-272.2002 ◽

2002 ◽

Vol 1 (2) ◽

pp. 257-272 ◽

Cited By ~ 92

Author(s):

Ping Wang ◽

Connie B. Nichols ◽

Klaus B. Lengeler ◽

Maria E. Cardenas ◽

Gary M. Cox ◽

...

Keyword(s):

Cryptococcus Neoformans ◽

Mating Type ◽

Fungal Pathogen ◽

Sexual Cycle ◽

Type Locus ◽

Serotype A ◽

A Cells ◽

Genes Encoding ◽

Opportunistic Fungal Pathogen ◽

Synthetically Lethal

ABSTRACT Cryptococcus neoformans is an opportunistic fungal pathogen with a defined sexual cycle involving fusion of haploid MATα and MATa cells. Virulence has been linked to the mating type, and MATα cells are more virulent than congenic MATa cells. To study the link between the mating type and virulence, we functionally analyzed three genes encoding homologs of the p21-activated protein kinase family: STE20α, STE20a, and PAK1. In contrast to the STE20 genes that were previously shown to be in the mating-type locus, the PAK1 gene is unlinked to the mating type. The STE20α, STE20a, and PAK1 genes were disrupted in serotype A and D strains of C. neoformans, revealing central but distinct roles in mating, differentiation, cytokinesis, and virulence. ste20α pak1 and ste20a pak1 double mutants were synthetically lethal, indicating that these related kinases share an essential function. In summary, our studies identify an association between the STE20α gene, the MATα locus, and virulence in a serotype A clinical isolate and provide evidence that PAK kinases function in a MAP kinase signaling cascade controlling the mating, differentiation, and virulence of this fungal pathogen.

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Faculty Opinions recommendation of The phocein homologue SmMOB3 is essential for vegetative cell fusion and sexual development in the filamentous ascomycete Sordaria macrospora.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.7817956.8155054 ◽

2011 ◽

Author(s):

Ulrich Kueck

Keyword(s):

Cell Fusion ◽

Sexual Development ◽

Vegetative Cell ◽

Sordaria Macrospora ◽

Filamentous Ascomycete

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Anion Inhibition Studies of the β-Class Carbonic Anhydrase CAS3 from the Filamentous Ascomycete Sordaria macrospora

Metabolites ◽

10.3390/metabo10030093 ◽

2020 ◽

Vol 10 (3) ◽

pp. 93

Author(s):

Daniela Vullo ◽

Ronny Lehneck ◽

William A. Donald ◽

Stefanie Pöggeler ◽

Claudiu T. Supuran

Keyword(s):

Catalytic Activity ◽

Carbonic Anhydrase ◽

Small Molecules ◽

Small Molecule ◽

Hydration Reaction ◽

High Catalytic Activity ◽

Sordaria Macrospora ◽

Filamentous Ascomycete ◽

Diethyl Dithiocarbamate ◽

Inhibition Studies

CAS3 is a newly cloned cytosolic β-class carbonic anhydrase (CA, EC 4.2.1.1) from the filamentous ascomycete Sordaria macrospora. This enzyme has a high catalytic activity for the physiological CO2 hydration reaction and herein, we report the inhibition profile of CAS3 with anions and small molecules. The most effective CAS3 anions/small molecule inhibitors were diethyl-dithiocarbamate, sulfamide, sulfamate, phenyl boronic and phenyl arsonic acids, with KIs in the range of 0.89 mM–97 µM. Anions such as iodide, the pseudohalides, bicarbonate, carbonate, nitrate, nitrite, hydrogensulfide, stannate, selenate, tellurate, tetraborate, perrhenate, perruthenate, selenocyanide and trithiocarbonate were low millimolar CAS3 inhibitors. The light halides, sulfate, hydrogensulfite, peroxydisulfate, diphosphate, divanadate, perchlorate, tetrafluoroborate, fluorosulfonate and iminodisulfonate did not significantly inhibit this enzyme. These data may be useful for developing antifungals based on CA inhibition, considering the fact that many of the inhibitors reported here may be used as lead molecules and, by incorporating the appropriate organic scaffolds, potent nanomolar inhibitors could be developed.

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Pheromones Stimulate Mating and Differentiation via Paracrine and Autocrine Signaling in Cryptococcus neoformans

Eukaryotic Cell ◽

10.1128/ec.1.3.366-377.2002 ◽

2002 ◽

Vol 1 (3) ◽

pp. 366-377 ◽

Cited By ~ 73

Author(s):

Wei-Chiang Shen ◽

Robert C. Davidson ◽

Gary M. Cox ◽

Joseph Heitman

Keyword(s):

Cryptococcus Neoformans ◽

Morphological Changes ◽

Pathogenic Fungus ◽

Tube Formation ◽

Mitogen Activated Protein Kinase ◽

Sexual Cycle ◽

Autocrine Signaling ◽

Type Locus ◽

A Cells ◽

Genes Encoding

ABSTRACT Cryptococcus neoformans is a pathogenic fungus with a defined sexual cycle involving haploid MATα and MATa cells. Interestingly, MATα strains are more common, are more virulent than congenic MATa strains, and undergo haploid fruiting in response to nitrogen limitation or MATa cells. Three genes encoding the MFα pheromone were identified in the MATα mating-type locus and shown to be transcriptionally induced by limiting nutrients and coculture with MATa cells. The MFα1, MFα2, and MFα3 genes were mutated, individually and in combination. MATα strains lacking MFα pheromone failed to induce morphological changes in MATa cells. Pheromoneless MATα mutants were fusion and mating impaired but not sterile and mated at ∼1% the wild-type level. The pheromoneless MATα mutants were also partially defective in haploid fruiting, and overexpression of MFα pheromone enhanced haploid fruiting. Overexpression of MFa pheromone also enhanced haploid fruiting of MATα cells and stimulated conjugation tube formation in MATa cells. A conserved G-protein activated mitogen-activated protein kinase signaling pathway was found to be required for both induction and response to mating pheromones. The MFα pheromone was not essential for virulence of C. neoformans but does contribute to the overall virulence composite. These studies define paracrine and autocrine pheromone response pathways that signal mating and differentiation of this pathogenic fungus.

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