Project description:Antisense (as)lncRNAs are extensively degraded by the nuclear exosome and the cytoplasmic exoribonuclease Xrn1 in the budding yeast Saccharomyces cerevisiae, lacking RNA interference (RNAi). Whether the ribonuclease III Dicer affects aslncRNAs in close RNAi-capable relatives remains unknown. Using genome-wide RNA profiling, here we show that aslncRNAs are primarily targeted by the exosome and Xrn1 in the RNAi-capable budding yeast Naumovozyma castellii, Dicer only affecting Xrn1-sensitive lncRNAs (XUTs) levels in Xrn1-deficient cells. The dcr1 and xrn1 mutants display synergic growth defects, indicating that Dicer becomes critical in absence of Xrn1. Small RNA sequencing showed that Dicer processes aslncRNAs into small RNAs, with a preference for asXUTs. Consistently, Dicer localizes into the cytoplasm. Finally, we observed an expansion of the exosome-sensitive antisense transcriptome in N. castellii compared to S. cerevisiae, suggesting that the presence of cytoplasmic RNAi has reinforced the nuclear RNA surveillance machinery to temper aslncRNAs expression. Our data provide fundamental insights into aslncRNAs metabolism and open perspectives into the possible evolutionary contribution of RNAi in shaping the aslncRNAs transcriptome.
Project description:Antisense (as)lncRNAs are extensively degraded by the nuclear exosome and the cytoplasmic exoribonuclease Xrn1 in the budding yeast Saccharomyces cerevisiae, lacking RNA interference (RNAi). Whether the ribonuclease III Dicer affects aslncRNAs in close RNAi-capable relatives remains unknown. Using genome-wide RNA profiling, here we show that aslncRNAs are primarily targeted by the exosome and Xrn1 in the RNAi-capable budding yeast Naumovozyma castellii, Dicer only affecting Xrn1-sensitive lncRNAs (XUTs) levels in Xrn1-deficient cells. The dcr1 and xrn1 mutants display synergic growth defects, indicating that Dicer becomes critical in the absence of Xrn1. Small RNA sequencing showed that Dicer processes aslncRNAs into small RNAs, with a preference for asXUTs. Consistently, Dicer localizes into the cytoplasm. Finally, we observed an expansion of the exosome-sensitive antisense transcriptome in N. castellii compared to S. cerevisiae, suggesting that the presence of cytoplasmic RNAi has reinforced the nuclear RNA surveillance machinery to temper aslncRNAs expression. Our data provide fundamental insights into aslncRNAs metabolism and open perspectives into the possible evolutionary contribution of RNAi in shaping the aslncRNAs transcriptome.
Project description:Antisense (as)lncRNAs are extensively degraded by the nuclear exosome and the cytoplasmic exoribonuclease Xrn1 in the budding yeast Saccharomyces cerevisiae, lacking RNA interference (RNAi). Whether the ribonuclease III Dicer affects aslncRNAs in close RNAi-capable relatives remains unknown. Using genome-wide RNA profiling, here we show that aslncRNAs are primarily targeted by the exosome and Xrn1 in the RNAi-capable budding yeast Naumovozyma castellii, Dicer only affecting Xrn1-sensitive lncRNAs (XUTs) levels in Xrn1-deficient cells. The dcr1 and xrn1 mutants display synergic growth defects, indicating that Dicer becomes critical in the absence of Xrn1. Small RNA sequencing showed that Dicer processes aslncRNAs into small RNAs, with a preference for asXUTs. Consistently, Dicer localizes into the cytoplasm. Finally, we observed an expansion of the exosome-sensitive antisense transcriptome in N. castellii compared to S. cerevisiae, suggesting that the presence of cytoplasmic RNAi has reinforced the nuclear RNA surveillance machinery to temper aslncRNAs expression. Our data provide fundamental insights into aslncRNAs metabolism and open perspectives into the possible evolutionary contribution of RNAi in shaping the aslncRNAs transcriptome.
Project description:RNA interference (RNAi) is a gene-silencing pathway that can play roles in viral defense, transposon silencing, heterochromatin formation, and post-transcriptional gene silencing. Although absent from Saccharomyces cerevisiae, RNAi is present in other budding-yeast species, including Naumovozyma castellii, which have an unusual Dicer and a conventional Argonaute that are both required for gene silencing. To identify other factors that act in the budding-yeast pathway, we performed an unbiased genetic selection. This selection identified Xrn1p, the cytoplasmic 5′-to-3′ exoribonuclease, as a cofactor of RNAi in budding yeast. Deletion of XRN1 impaired gene silencing in N. castellii, and this impaired silencing was attributable to multiple functions of Xrn1p, including affecting the composition of siRNA species in the cell, influencing the efficiency of siRNA loading into Argonaute, degradation of cleaved passenger strand, and degradation of sliced target RNA.
Project description:Unusually among fungi, Saccharomyces cerevisiae is able to grow in environments containing almost no oxygen. A major feature of its response to hypoxia is a transition in expression from aerobic to hypoxic genes, which often code for duplicated isoforms of the same protein. In aerobic conditions, expression of the hypoxic gene set is repressed by the HMG domain protein Rox1. Here, we examined the evolution of ROX1 and related genes in the subphylum Saccharomycotina and find that a substantial reorganization of hypoxic gene regulation occurred during yeast evolution. S. cerevisiae lost ROX2, an ancient paralog of ROX1, which is almost universally present in other yeast species. ROX2 is orthologous to Candida albicans RFG1, a regulator of filamentous growth. Many yeasts, such as Candida glabrata, lack ROX1 and contain only ROX2. Others such as Naumovozyma castellii retain both genes. Although the ancestral function of ROX2 is uncertain, we find that it is not a regulator of hypoxic genes except in C. glabrata where it has taken over this function from the absent ROX1. We also find that N. castellii has a greatly attenuated transcriptional response to hypoxia as compared to other species, but that the ergosterol pathway which is normally induced by hypoxia can be induced by cobalt chloride stress in N. castellii.
Project description:This is genome-scale metabolic model of Saccharomyces cerevisiae as the representative yeast species for the clade Saccharomycetaceae. This model was generated through homology search using a fungal pan-GEM largely based on Yeast8 for Saccharomyces cerevisiae, in addition to manual curation. This model has been produced by the Yeast-Species-GEMs project from Sysbio (www.sysbio.se). This is model version 1.0.0 accompanying the publication (DOI: 10.15252/msb.202110427), currently hosted on BioModels Database (http://www.ebi.ac.uk/biomodels/) and identified by MODEL2109130010. Further curations of this model will be tracked in the GitHub repository: https://github.com/SysBioChalmers/Yeast-Species-GEMs Models for species of the same clade includes: Ashbya aceri; Candida glabrata; Eremothecium coryli; Eremothecium cymbalariae; Eremothecium gossypii; Eremothecium sinecaudum; Kazachstania africana; Kazachstania naganishii; Kluyveromyces lactis; Kluyveromyces marxianus; Lachancea cidri; Lachancea dasiensis; Lachancea fantastica nom. nud.; Lachancea fermentati; Lachancea kluyveri; Lachancea lanzarotensis; Lachancea meyersii; Lachancea mirantina; Lachancea nothofagi; Lachancea quebecensis; Lachancea thermotolerans; Lachancea waltii; Nakaseomyces bacillisporus; Candida bracarensis; Candida castellii; Nakaseomyces delphensis; Candida nivariensis; Naumovozyma castellii; Naumovozyma dairenensis; Saccharomyces arboricola; Saccharomyces cerevisiae; Saccharomyces eubayanus; Saccharomyces kudriavzevii; Saccharomyces mikatae; Saccharomyces paradoxus; Saccharomyces uvarum; Tetrapisispora blattae; Tetrapisispora phaffii; Torulaspora delbrueckii; Vanderwaltozyma polyspora; Zygosaccharomyces bailii; Zygosaccharomyces rouxii; Kazachstania martiniae; Kazachstania unispora; Kazachstania turicensis; Kazachstania bromeliacearum; Kazachstania siamensis; Kazachstania taianensis; Kazachstania intestinalis; Kazachstania rosinii; Kazachstania transvaalensis; Kazachstania spencerorum; Kazachstania viticola; Kazachstania solicola; Kazachstania kunashirensis; Kazachstania aerobia; Kazachstania yakushimaensis; Torulaspora franciscae; Zygotorulaspora mrakii; Kluyveromyces aestuarii; Kluyveromyces dobzhanskii; Zygotorulaspora florentina; Zygosaccharomyces kombuchaensis; Zygosaccharomyces bisporus; Tetrapisispora fleetii; Tetrapisispora iriomotensis; Tetrapisispora namnaonensis; Torulaspora pretoriensis; Yueomyces sinensis; Torulaspora microellipsoides; Torulaspora maleeae. These models are available in the zip file. To cite BioModels, please use: V Chelliah et al; BioModels: ten-year anniversary. Nucleic Acids Res 2015; 43 (D1): D542-D548. 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 MIT License for more information.
FROG and miniFROG reports of the models for iPN730 (Lachancea kluyveri) and iSM996 (Kluyveromyces marxianus) also updated.
Project description:RNAi, a gene-silencing pathway triggered by double-stranded RNA, is conserved in diverse eukaryotic species but has been lost in the model budding yeast, Saccharomyces cerevisiae. We report that RNAi is present in other budding-yeast species, including Saccharomyces castellii and Candida albicans. These species use noncanonical Dicer proteins to generate siRNAs, which mostly correspond to transposable elements and YM-BM-4 subtelomeric repeats. In S. castellii, RNAi mutants are viable but have excess YM-BM-4 mRNA levels. In S. cerevisiae, introducing Dicer and Argonaute of S. castellii restores RNAi, and the reconstituted pathway silences endogenous retrotransposons. These results identify a novel class of Dicer proteins, bring the tool of RNAi to the study of budding yeasts, and bring the tools of budding yeast to the study of RNAi. Employ high-throughput sequencing of endogenous small RNAs from the budding yeasts Saccharomyces castellii, Kluyveromyces polysporus, Candida albicans, Saccharomyces cerevisiae, and Saccharomyces bayanus.