Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The cell-fate decision leading to gametogenesis is essential for sexual reproduction. In S. cerevisiae, only diploid MATa/α but not haploid MATa or MATα cells undergo gametogenesis, known as sporulation. We find that transcription of two long noncoding RNAs (lncRNAs) mediates mating-type control of sporulation. In MATa or MATα haploids, expression of IME1, the central inducer of gametogenesis, is inhibited in cis by transcription of the lncRNA IRT1, located in the IME1 promoter. IRT1 transcription recruits the Set2 histone methyltransferase and the Set3 histone deacetylase complex to establish repressive chromatin at the IME1 promoter. Inhibiting expression of IRT1 and an antisense transcript that antagonizes the expression of the meiotic regulator IME4 allows cells expressing the haploid mating type to sporulate with kinetics that are indistinguishable from that of MATa/α diploids. Conversely, expression of the two lncRNAs abolishes sporulation in MATa/α diploids. Thus, transcription of two lncRNAs governs mating-type control of gametogenesis in yeast.
ISSN: 0092-8674

hal-00877439
https://hal.archives-ouvertes.fr/hal-00877439
DOI : 10.1016/j.cell.2012.06.049
PUBMED : 22959267

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Diploid budding yeast undergoes rapid mitosis when it ferments glucose, and in the presence of a non-fermentable carbon source and the absence of a nitrogen source it triggers sporulation. Rich medium with acetate is a commonly used pre-sporulation medium, but our understanding of the molecular events underlying the acetate-driven transition from mitosis to meiosis is still incomplete. We identified 263 proteins for which mRNA and protein synthesis are linked or uncoupled in fermenting and respiring cells. Using motif predictions, interaction data and RNA profiling we find among them 28 likely targets for Ume6, a subunit of the conserved Rpd3/Sin3 histone deacetylase-complex regulating genes involved in metabolism, stress response and meiosis. Finally, we identify 14 genes for which both RNA and proteins are detected exclusively in respiring cells but not in fermenting cells in our sample set, including CSM4, SPR1, SPS4 and RIM4, which were thought to be meiosis-specific. Our work reveals intertwined transcriptional and post-transcriptional control mechanisms acting when a MATa/α strain responds to nutritional signals, and provides molecular clues how the carbon source primes yeast cells for entering meiosis. Our integrated genomics study provides insight into the interplay between the transcriptome and the proteome in diploid yeast cells undergoing vegetative growth in the presence of glucose (fermentation) or acetate (respiration). Furthermore, it reveals novel target genes involved in these processes for Ume6, the DNA binding subunit of the conserved histone deacetylase Rpd3 and the co-repressor Sin3. We have combined data from an RNA profiling experiment using tiling arrays that cover the entire yeast genome, and a large-scale protein detection analysis based on mass spectrometry in diploid MATa/α cells. This distinguishes our study from most others in the field-which investigate haploid yeast strains-because only diploid cells can undergo meiotic development in the simultaneous absence of a non-fermentable carbon source and nitrogen. Indeed, we report molecular clues how respiration of acetate might prime diploid cells for efficient spore formation, a phenomenon that is well known but poorly understood.
ISSN: 1874-3919

hal-01122122
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122122
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122122/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01122122/file/Integrated%20RNA-%20and%20protein%20profiling%20of%20fermentation.pdf
DOI : 10.1016/j.jprot.2015.01.015