Project description:Cellular differentiation is instructed by development regulators in coordination with chromatin remodeling complexes. Much information about their coordination comes from studies in the model ascomycetous yeasts. It is not clear, however, of the kind of information that can be extrapolated to species of other phyla in Kingdom Fungi. In the basidiomycete Cryptococcus neoformans, the transcription factor Znf2 controls yeast-to-hypha differentiation. Through a forward genetic screen, we identified the basidiomycete-specific factor Brf1 and discovered that it works together with Snf5 in the SWI/SNF chromatin remodeling complex in concert with existent Znf2 to execute cellular differentiation. We demonstrated that SWI/SNF assists Znf2 opening up the promoter regions of hyphal specific genes, including the ZNF2 gene itself. In addition, this complex supports Znf2 to fully associate with its target regions. Importantly, our findings revealed key differences in composition and biological function of the SWI/SNF complex in the two major phyla of Kingdom Fungi.
Project description:Here we announce the complete genome sequence of the coenzyme B(12)-producing enteric bacterium Shimwellia blattae (formerly Escherichia blattae). The genome consists of a single chromosome (4,158,636 bp). The genome size is smaller than that of most other enteric bacteria. Genome comparison revealed significant differences from the Escherichia coli genome.
Project description:Adaptation to alkalinization of the medium in fungi involves an extensive remodeling of gene expression. Komagataella phaffii is an ascomycetous yeast that has become an organism widely used for heterologous protein expression. We explore here the transcriptional impact of moderate alkalinization in this yeast. In spite of a minor effect on growth, shifting the cultures from pH 5.5 to 8.0 or 8.2 provokes significant changes in the mRNA levels of over 700 genes. Functional categories such as arginine and methionine biosynthesis, non-reductive iron uptake and phosphate metabolism are enriched in induced genes, whereas many genes encoding iron-sulfur proteins or members of the respirasome were repressed. We also show that alkalinization is accompanied by oxidative stress and we propose this circumstance as a common trigger of a subset of the observed changes. PHO89, encoding a Na+/Pi cotransporter, appears among the most potently induced genes by high pH. We demonstrate that this response is mainly based on two calcineurin-dependent response elements located in its promoter, thus indicating that alkalinization triggers a calcium-mediated signal in K. phaffii. Further characterization of alkaline pH responsive promoters may lead to developing novel pH-controlled systems for heterologous protein expression in this fungus.
Project description:Zygotorulaspora dagestanica sp. nov., a novel ascomycetous yeast species associated with the Georgian honeysuckle (Lonicera iberica M. Bieb.)
Project description:The structure of Escherichia blattae non-specific acid phosphatase (EB-NSAP) has been determined at 1.9 A resolution with a bound sulfate marking the phosphate-binding site. The enzyme is a 150 kDa homohexamer. EB-NSAP shares a conserved sequence motif not only with several lipid phosphatases and the mammalian glucose-6-phosphatases, but also with the vanadium-containing chloroperoxidase (CPO) of Curvularia inaequalis. Comparison of the crystal structures of EB-NSAP and CPO reveals striking similarity in the active site structures. In addition, the topology of the EB-NSAP core shows considerable similarity to the fold of the active site containing part of the monomeric 67 kDa CPO, despite the lack of further sequence identity. These two enzymes are apparently related by divergent evolution. We have also determined the crystal structure of EB-NSAP complexed with the transition-state analog molybdate. Structural comparison of the native enzyme and the enzyme-molybdate complex reveals that the side-chain of His150, a putative catalytic residue, moves toward the molybdate so that it forms a hydrogen bond with the metal oxyanion when the molybdenum forms a covalent bond with NE2 of His189.
