The APSES protein Sok2 is a positive regulator of sporulation in <i>Ashbya gossypii</i>

Wasserstrom, Lisa; Dünkler, Alexander; Walther, Andrea; Wendland, Jürgen

doi:10.1111/mmi.13859

Cited by 11 publications

(9 citation statements)

References 55 publications

(82 reference statements)

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“…Regarding the riboflavin production in A. gossypii, one missense homozygous mutation (1180G → A) was detected in AgSOK2 gene (AGOS_ABR055C) of MT strain. AgSOK2 is one of fungal-specific group of transcription factors and involved in the sporulation and riboflavin production in A. gossypii [34]. Deletion of AgSOK2 gene led to the strong reduction of the riboflavin production and the deficiency of the sporulation by the downregulation of AgIME2 and AgNDT80 gene.…”

Section: Resultsmentioning

confidence: 99%

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

et al. 2020

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Background: Ashbya gossypii naturally overproduces riboflavin and has been utilized for industrial riboflavin production. To improve riboflavin production, various approaches have been developed. In this study, to investigate the change in metabolism of a riboflavin-overproducing mutant, namely, the W122032 strain (MT strain) that was isolated by disparity mutagenesis, genomic analysis was carried out. Results: In the genomic analysis, 33 homozygous and 1377 heterozygous mutations in the coding sequences of the genome of MT strain were detected. Among these heterozygous mutations, the proportion of mutated reads in each gene was different, ranging from 21 to 75%. These results suggest that the MT strain may contain multiple nuclei containing different mutations. We tried to isolate haploid spores from the MT strain to prove its ploidy, but this strain did not sporulate under the conditions tested. Heterozygous mutations detected in genes which are important for sporulation likely contribute to the sporulation deficiency of the MT strain. Homozygous and heterozygous mutations were found in genes encoding enzymes involved in amino acid metabolism, the TCA cycle, purine and pyrimidine nucleotide metabolism and the DNA mismatch repair system. One homozygous mutation in AgILV2 gene encoding acetohydroxyacid synthase, which is also a flavoprotein in mitochondria, was found. Gene ontology (GO) enrichment analysis showed heterozygous mutations in all 22 DNA helicase genes and genes involved in oxidation-reduction process. Conclusion: This study suggests that oxidative stress and the aging of cells were involved in the riboflavin overproduction in A. gossypii riboflavin over-producing mutant and provides new insights into riboflavin production in A. gossypii and the usefulness of disparity mutagenesis for the creation of new types of mutants for metabolic engineering.

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Section: Resultsmentioning

confidence: 99%

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

et al. 2020

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“…It is likely that in O . polymorpha PKA regulates EFG1 to signal nitrogen depletion, because PKA is known to regulate Efg1 orthologs in Eremothecium (Ashbya) gossypii [ 59 ] and S . cerevisiae [ 28 , 57 ], as well as C .…”

Section: Discussionmentioning

confidence: 99%

Flip/flop mating-type switching in the methylotrophic yeast Ogataea polymorpha is regulated by an Efg1-Rme1-Ste12 pathway

2017

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In haploid cells of Ogataea (Hansenula) polymorpha an environmental signal, nitrogen starvation, induces a reversible change in the structure of a chromosome. This process, mating-type switching, inverts a 19-kb DNA region to place either MATa or MATα genes under centromeric repression of transcription, depending on the orientation of the region. Here, we investigated the genetic pathway that controls switching. We characterized the transcriptomes of haploid and diploid O. polymorpha by RNAseq in rich and nitrogen-deficient media, and found that there are no constitutively a-specific or α-specific genes other than the MAT genes themselves. We mapped a switching defect in a sibling species (O. parapolymorpha strain DL-1) by interspecies bulk segregant analysis to a frameshift in the transcription factor EFG1, which in Candida albicans regulates filamentous growth and white-opaque switching. Gene knockout, overexpression and ChIPseq experiments show that EFG1 regulates RME1, which in turn regulates STE12, to achieve mating-type switching. All three genes are necessary both for switching and for mating. Overexpression of RME1 or STE12 is sufficient to induce switching without a nitrogen depletion signal. The homologous recombination genes RAD51 and RAD17 are also necessary for switching. The pathway controlling switching in O. polymorpha shares no components with the regulation of HO in S. cerevisiae, which does not involve any environmental signal, but it shares some components with mating-type switching in Kluyveromyces lactis and with white-opaque phenotypic switching in C. albicans.

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“…Interestingly, we found that a fungal specific transcription factor, encoded by the APSES protein Sok2, is downregulated in an α2 overexpressing strain. SOK2 deletion completely blocks sporulation (although not sporangium formation), e.g., via downregulation of IME2 [58]. Thus, the effect of α2 overexpression may be indirect.…”

Section: The Gear-box Of Sporulationmentioning

confidence: 99%

Sporulation in Ashbya gossypii

Wendland

2020

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Ashbya gossypii is a filamentous ascomycete belonging to the yeast family of Saccharomycetaceae. At the end of its growth phase Ashbya generates abundant amounts of riboflavin and spores that form within sporangia derived from fragmented cellular compartments of hyphae. The length of spores differs within species of the genus. Needle-shaped Ashbya spores aggregate via terminal filaments. A. gossypii is a homothallic fungus which may possess a and α mating types. However, the solo-MATa type strain is self-fertile and sporulates abundantly apparently without the need of prior mating. The central components required for the regulation of sporulation, encoded by IME1, IME2, IME4, KAR4, are conserved with Saccharomyces cerevisiae. Nutrient depletion generates a strong positive signal for sporulation via the cAMP-PKA pathway and SOK2, which is also essential for sporulation. Strong inhibitors of sporulation besides mutations in the central regulatory genes are the addition of exogenous cAMP or the overexpression of the mating type gene MATα2. Sporulation has been dissected using gene-function analyses and global RNA-seq transcriptomics. This revealed a role of Msn2/4, another potential PKA-target, for spore wall formation and a key dual role of the protein A kinase Tpk2 at the onset of sporulation as well as for breaking the dormancy of spores to initiate germination. Recent work has provided an overview of ascus development, regulation of sporulation and spore maturation. This will be summarized in the current review with a focus on the central regulatory genes. Current research and open questions will also be discussed.

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The APSES protein Sok2 is a positive regulator of sporulation in Ashbya gossypii

Cited by 11 publications

References 55 publications

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis

Flip/flop mating-type switching in the methylotrophic yeast Ogataea polymorpha is regulated by an Efg1-Rme1-Ste12 pathway

Sporulation in Ashbya gossypii

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