Biology subjects

Dube, A. K.

Publications and source records attributed to Dube, A. K..

26 records · Page 2Linked to original sources

bioRxiv2022

Evolutionary trajectories are contingent on mitonuclear interactions

Critical mitochondrial functions, including cellular respiration, rely on frequently interacting components expressed from both the mitochondrial and nuclear genomes. The fitness of eukaryotic organisms depends on a tight collaboration between both genomes. In the face of an elevated rate of evolution in the mitochondrial genome, current models predict that maintenance of mitonuclear compatibility relies on compensatory evolution of the nuclear genome. Mitonuclear interactions would therefore exert an influence on evolutionary trajectories. One prediction from this model is that the same nuclear genomes but evolving with different mitochondrial haplotypes would follow distinct molecular paths towards higher fitness peaks. To test this prediction, we submitted 1344 populations derived from seven mitonuclear genotypes of Saccharomyces cerevisiae to more than 300 generations of experimental evolution in conditions that either select for a mitochondrial function, or that do not strictly require respiration for survival. Performing high-throughput phenotyping and whole-genome sequencing on independently evolved individuals isolated from endpoint populations, we identified numerous examples of gene-level evolutionary convergence among populations with the same mitonuclear background. Phenotypic and genotypic data on strains derived from this evolution experiment identify the nuclear genome and the environment as the main determinants of evolutionary divergence, but also show a modulating role for the mitochondrial genome exerted both directly and via interactions with the two other components. We finally recapitulated a subset of prominent loss-of-function alleles in the ancestral backgrounds and confirmed a generalized pattern of mitonuclear-specific and highly epistatic fitness effects. Together, these results demonstrate how mitonuclear interactions can dictate evolutionary divergence of populations with identical starting nuclear genotypes.

evolutionary biology↗

bioRxiv2022

Epistasis between promoter activity and coding mutations shapes gene evolvability

The evolution of protein-coding genes proceeds as mutations act on two main dimensions: regulation of transcription level and the coding sequence. The extent and impact of the connection between these two dimensions are largely unknown because they have generally been studied independently. By measuring the fitness effects of all possible mutations on a protein complex at various levels of promoter activity, we show that expression at the optimal level for the WT protein masks the effects of both deleterious and beneficial coding mutations. Mutants that are deleterious at low expression but masked at optimal expression are slightly destabilizing for individual subunits and binding interfaces. Coding mutations that increase protein abundance are beneficial at low expression but incur a fitness cost at high expression. We thereby demonstrate that expression level can dictate which coding mutations are beneficial or deleterious.

evolutionary biology↗

bioRxiv2021

Asymmetrical dose-response shape the evolutionary trade-off between antifungal resistance and nutrient use

Antimicrobial resistance is an emerging threat for public health. The success of resistance mutations depends on the trade-off between the benefits and costs they incur. This trade-off is largely unknown and uncharacterized for antifungals. Here, we systematically measure the effect of all amino acid substitutions in the yeast cytosine deaminase Fcy1, the target of the antifungal 5-FC (flucytosine). We identify over 900 missense mutations granting resistance to 5-FC, a large fraction of which appear to act through destabilisation of the protein. The relationship between 5-FC resistance and growth sustained by cytosine deamination is characterized by a sharp trade-off, such that small gains in resistance universally lead to large losses in canonical enzyme function. We show that this steep relationship can be explained by differences in the dose-response functions of 5-FC and cytosine. Finally, we observe the same trade-off shape for the ortholog of FCY1 in Cryptoccocus neoformans, a human pathogen. Our results provide a powerful resource and platform for interpreting drug target variants in fungal pathogens as well as unprecedented insights into resistance-function trade-offs.

evolutionary biology↗

bioRxiv2021

BFG-PCA: tools and resources that expand the potential for binary protein interaction discovery

Barcode fusion genetics (BFG) utilizes deep sequencing to improve the throughput of protein-protein interaction (PPI) screening in pools. BFG has been implemented in Yeast two-hybrid (Y2H) screens (BFG-Y2H). While Y2H requires test protein pairs to localize in the nucleus for reporter reconstruction, Dihydrofolate Reductase Protein-Fragment Complementation Assay (DHFR-PCA) allows proteins to localize in broader subcellular contexts and proves to be largely orthogonal to Y2H. Here, we implemented BFG to DHFR-PCA (BFG-PCA). This plasmid-based system can leverage ORF collections across model organisms to perform comparative analysis, unlike the original DHFR-PCA that requires yeast genomic integration. The scalability and quality of BFG-PCA were demonstrated by screening human and yeast interactions for >11,000 protein pairs. BFG-PCA showed high-sensitivity and high-specificity for capturing known interactions for both species. BFG-Y2H and BFG-PCA capture distinct sets of PPIs, which can partially be explained based on the domain orientation of the reporter tags. BFG-PCA is a high-throughput protein interaction technology to interrogate binary PPIs that exploits clone collections from any species of interest, expanding the scope of PPI assays.

systems biology↗

bioRxiv2021

Rewiring the Three-Carbon Metabolism Abrogates Multiple MAPK-Induced Cellular Dysfunctions During Metabolic Disorder

Withdrawal noticeThe authors have withdrawn their manuscript. The lipidomic data presented in the manuscript were based on an excel summary sheet provided by VIT, whose group (AP and KM) conducted the analysis using an Orbitrap mass spectrometer. However, after submitting to BioRxiv, the VIT group could not recover the RAW (primary source) files from the lipidomic platform because these files were deleted due to the maintenance protocol used for the Orbitrap mass spectrometer. It was agreed to reconduct the lipidomic analysis. As the Orbitrap mass spectrometer was out of service at that time, the lipidomic analysis was conducted with the help of a QToF mass spectrometer. Important differences were noted for the relative abundance and species of many lipids across the strains compared to the previously reported data hence casting some doubt on their interpretation. Therefore, until further analysis can be carried out the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

cell biology↗

bioRxiv2020

The specificity of SRC Homology 3 (SH3) domain interactions is modulated by their protein context in vivo

Protein-protein interactions (PPIs) between modular binding domains and their target peptide motifs are thought to largely depend on the intrinsic binding specificities of the domains. By combining deletion, mutation, swapping and shuffling of SRC Homology 3 (SH3) domains and measuring their impact on protein interactions, we find that most SH3s do not autonomously dictate PPI specificity in vivo. The identity of the host protein and the position of the SH3 domains within their host are both critical for PPI specificity, for cellular functions and for key biophysical processes such as phase separation. Our work demonstrates the importance of the interplay between a modular PPI domain such as SH3 and its host protein in establishing specificity to wire PPI networks.Competing Interest StatementThe authors have declared no competing interest.View Full Text

systems biology↗

bioRxiv2019

Systematic perturbation of yeast essential genes using base editing

Base editors derived from CRISPR-Cas9 systems and DNA editing enzymes offer an unprecedented opportunity for the precise modification of genes, but have yet to be used at a genome-scale throughput. Here, we test the ability of an editor based on a cytidine deaminase, the Target-AID base editor, to systematically modify genes genome-wide using the set of yeast essential genes. We tested the effect of mutating around 17,000 individual sites in parallel across more than 1,500 genes in a single experiment. We identified over 1,100 sites at which mutations have a significant impact on fitness. Using previously determined and preferred Target-AID mutational outcomes, we predicted the protein variants caused by each of these gRNAs. We found that gRNAs with significant effects on fitness are enriched in variants predicted to be deleterious by independent methods based on site conservation and predicted protein destabilization. Finally, we identify key features to design effective gRNAs in the context of base editing. Our results show that base editing is a powerful tool to identify key amino acid residues at the scale of proteomes.

synthetic biology↗

bioRxiv2018

Highly efficient CRISPR gene editing in yeast enabled by double selection

CRISPR-Cas9 loss of function (LOF) and base editing screens are powerful tools in genetics and genomics. Yeast is one of the main models in genetics and genomics, yet large-scale approaches remain to be developed in this species because of low mutagenesis rates without donor DNA. We developed a double selection strategy based on co-selection that increases LOF mutation rates, both for CRISPR-Cas9 and the Target-AID base editor. We constructed the pDYSCKO vector, which is amenable to high throughput double selection for both approaches. Using modeling, we show that this improvement provides the required increased in detection power to measure the fitness effects of thousands of mutations in typical yeast pooled screens. We also show that multiplex genome editing with Cas9 causes programmable chromosomal translocations at high frequency, suggesting that multiplex editing should be performed with caution and that base-editors could be preferable tools for LOF screens.

synthetic biology↗