Project description:To evaluate role of PRC2 on transcriptional regulation in Cyanidioschyzon merolae, we generated loss of function mutants of a Ez homolog in Cyanidioschyzon merolae by homologous recombination based mutagenesis. Then we performed comparative transcriptome analyses using data obtained from Cme(z) and WT.
Project description:Cyanidioschyzon merolae is a thermophilic red alga with an optimum growth temperature of 42°C. In this study we investigated the acclimation process of the alga to a colder temperature (25°C). To this aim we performed quantitative proteomic analyses of whole cells as well as solubilized thylakoid protein complexes.
Project description:A powerful way to enhance heat tolerance is by establishing a stress memory through exposure to a heat stress that is strong enough to induce a molecular stress response without causing irreversible damage, followed by a recovery phase. While this has been extensively studied in multicellular organisms, we demonstrate that heat stress memory is also present in the unicellular red alga Cyanidioschyzon merolae. We show that, similarly to more complex organisms, thermomemory in this alga is underpinned by transcriptomic reprogramming, with the chloroplast emerging as the main site of gene trainability. Additionally, we find a conserved small heat shock protein (sHSP)-encoding locus in the nuclear genome to be heat-trainable, likely by histone depletion and modification through the repressive mark H3K27me3. We show that of C. merolae’s two sHSPs, only CmsHSP2 is necessary for proper HS memory establishment, and that the two sHSPs localize to different cellular compartments during heat stress. Finally, comparative RNA-Sequencing of an Enhancer of zeste mutant reveals a role for the H3K27me3-transferase in adapting the transcriptome to recurring heat exposures, beyond regulating the trainable sHSP locus.