The fission yeast rDNA-binding protein Reb1 regulates G1 phase under nutritional stress

Rodríguez-Sánchez, Leonor; Rodríguez-López, Maria; García, Zaira; Tenorio-Gómez, María; Schvartzman, Jorge Bernardo; Krimer, Dora B.; Hernández, Pablo

doi:10.1242/jcs.070987

Cited by 23 publications

(19 citation statements)

References 35 publications

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“…Under these conditions, FlbD might perform additional functions in nitrogen signaling or utilization. In Schizosaccharomyces pombe, the Mybtype DNA binding protein Reb1 regulates G 1 cell cycle arrest and sexual differentiation in response to nitrogen starvation (55), while in the unicellular red alga Cyanidioschyzon merolae Cm-MYB1, an R2R3-type Myb TF activates expression of key nitrogen assimilation genes in response to nitrogen status (28).…”

Section: Discussionmentioning

confidence: 99%

FlbD, a Myb Transcription Factor of Aspergillus nidulans, Is Uniquely Involved in both Asexual and Sexual Differentiation

et al. 2012

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ABSTRACTIn the fungusAspergillus nidulans, inactivation of theflbAto-E,fluG,fluF, andtmpAgenes results in similar phenotypes, characterized by a delay in conidiophore and asexual spore production.flbBto-Dencode transcription factors needed for proper expression of thebrlAgene, which is essential for asexual development. However, recent evidence indicates that FlbB and FlbE also have nontranscriptional functions. Here we show thatfluF1is an allele offlbDwhich results in an R47P substitution. Amino acids C46 and R47 are highly conserved in FlbD and many other Myb proteins, and C46 has been proposed to mediate redox regulation. Comparison of ΔflbDandflbDR47Pmutants uncovered a new and specific role forflbDduring sexual development. WhileflbDR47Pmutants retain partial function during conidiation, bothΔflbDandflbDR47Pmutants are unable to develop the peridium, a specialized external tissue that differentiates during fruiting body formation and ends up surrounding the sexual spores. This function, unique among otherfluffygenes, does not affect the viability of the naked ascospores produced by mutant strains. Notably, ascospore development in these mutants is still dependent on the NADPH oxidase NoxA. We generated R47K, C46D, C46S, and C46A mutant alleles and evaluated their effects on asexual and sexual development. Conidiation defects were most severe inΔflbDmutants and stronger in R47P, C46D, and C46S strains than in R47K strains. In contrast, mutants carrying theflbDC46Aallele exhibited conidiation defects in liquid culture only under nitrogen starvation conditions. The R47K, R47P, C46D, and C46S mutants failed to develop any peridial tissue, while theflbDC46Astrain showed normal peridium development and increased cleistothecium formation. Our results show that FlbD regulates both asexual and sexual differentiation, suggesting that both processes require FlbD DNA binding activity and that FlbD is involved in the response to nitrogen starvation.

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Section: Discussionmentioning

confidence: 99%

FlbD, a Myb Transcription Factor of Aspergillus nidulans, Is Uniquely Involved in both Asexual and Sexual Differentiation

et al. 2012

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“…67. The ura4 gene (promoter, ORF, terminator) was amplified from wild-type (JB32) genomic DNA using primers mp161 and mp162 and inserted into the pCR-2.1 vector by TA cloning (Invitrogen).…”

Section: Plasmids and Strain Constructionmentioning

confidence: 99%

CSL protein regulates transcription of genes required to prevent catastrophic mitosis in fission yeast

et al. 2016

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For every eukaryotic cell to grow and divide, intricately coordinated action of numerous proteins is required to ensure proper cell-cycle progression. The fission yeast Schizosaccharomyces pombe has been instrumental in elucidating the fundamental principles of cell-cycle control. Mutations in S. pombe 'cut' (cell untimely torn) genes cause failed coordination between cell and nuclear division, resulting in catastrophic mitosis. Deletion of cbf11, a fission yeast CSL transcription factor gene, triggers a 'cut' phenotype, but the precise role of Cbf11 in promoting mitotic fidelity is not known. We report that Cbf11 directly activates the transcription of the acetyl-coenzyme A carboxylase gene cut6, and the biotin uptake/ biosynthesis genes vht1 and bio2, with the former 2 implicated in mitotic fidelity. Cbf11 binds to a canonical, metazoan-like CSL response element (GTGGGAA) in the cut6 promoter. Expression of Cbf11 target genes shows apparent oscillations during the cell cycle using temperature-sensitive cdc25-22 and cdc10-M17 block-release experiments, but not with other synchronization methods. The penetrance of catastrophic mitosis in cbf11 and cut6 mutants is nutrient-dependent. We also show that drastic decrease in biotin availability arrests cell proliferation but does not cause mitotic defects. Taken together, our results raise the possibility that CSL proteins play conserved roles in regulating cell-cycle progression, and they could guide experiments into mitotic CSL functions in mammals.

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“…Tetrads, zygotes and cells were quantified by microscopic observation using a Neubauer chamber. The formula for calculating conjugation efficiency was 2Z/ (2Z + A), where Z is the number of zygotes plus asci formed and A is the number of non-mating cells expressed as a percentage (Rodríguez-Sánchez et al, 2011). At least 200 cells were counted in each culture.…”

Section: Stress Assaysmentioning

confidence: 99%

New roles of the fission yeast eIF2α kinases Hri1 and Gcn2 in response to nutritional stress

Martín

Berlanga

Haro

2013

Journal of Cell Science

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SummaryIn fission yeast, three distinct eukaryotic initiation factor 2a (eIF2a) kinases (Hri1, Hri2 and Gcn2), regulate protein synthesis in response to various environmental stresses. Thus, Gcn2 is activated early after exposure to hydrogen peroxide (H 2 O 2 ) and methyl methanesulfonate (MMS), whereas Hri2 is the primary activated eIF2a kinase in response to heat shock. The function of Hri1 is still not completely understood. It is also known that the mitogen-activated protein kinase Sty1 negatively regulates Gcn2 and Hri2 activities under oxidative stress. In this study, we demonstrate that Hri1 is mainly activated, and its expression upregulated, during transition from exponential growth to the stationary phase in response to nutritional limitation. Accordingly, both Hri1 and Gcn2, but not Hri2, are activated upon nitrogen source deprivation. In contrast, Hri2 is stimulated early during glucose starvation. We also found that Gcn2 is implicated in nitrogen starvation-induced growth arrest in the cell cycle G1 phase as well as in the non-selective protein degradation process caused upon this particular cellular stress. Moreover, Gcn2, but not Hri1 or Hri2, is essential for survival of cells growing in minimal medium, upon oxidative stress or glucose limitation. We further show that eIF2a phosphorylation at serine 52 by the eIF2a kinases is necessary for efficient cell cycle arrest in the G1 phase, for the consequent protein degradation and for sexual differentiation, under nitrogen starvation. Therefore, the eIF2a kinase signalling pathway modulates G1 phase cell cycle arrest, cell survival and mating under nutritional stress in the fission yeast Schizosaccharomyces pombe.

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The fission yeast rDNA-binding protein Reb1 regulates G1 phase under nutritional stress

Cited by 23 publications

References 35 publications

FlbD, a Myb Transcription Factor of Aspergillus nidulans, Is Uniquely Involved in both Asexual and Sexual Differentiation

FlbD, a Myb Transcription Factor of Aspergillus nidulans, Is Uniquely Involved in both Asexual and Sexual Differentiation

CSL protein regulates transcription of genes required to prevent catastrophic mitosis in fission yeast

New roles of the fission yeast eIF2α kinases Hri1 and Gcn2 in response to nutritional stress

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