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Landry, C.

Publications and source records attributed to Landry, C..

At least 19 recordsLinked to original sources
bioRxiv2026

Population genomics of Candida albicans reveals genetic footprints that allow the prediction of antifungal resistance

Rapid detection of drug resistance in fungi is becoming increasingly urgent. While multiple loci and mutations were linked to antifungal resistance in Candida albicans, the utility of whole genome sequencing in predicting resistance has not been tested thoroughly. We address this by integrating more than 1000 C. albicans genomes, with associated resistance phenotypes to six antifungals, a curated repository of resistance-causing mutations and variant effect predictors. We used Genome Wide Association Studies and Machine Learning approaches to associate genetic variants to resistance phenotypes. We found that well curated databases like FungAMR are able to accurately identify markers predictive antifungal resistance. Curated mutations were detected in 56 to 74% of isolates with reduced azole susceptibility and 57 to 90% of those with reduced echinocandin susceptibility, revealing incomplete coverage of resistance across both drug classes. Complementary variant- and gene-level association analyses recovered established resistance determinants and uncovered additional candidate loci, whereas copy-number changes provided limited independent explanatory power. Genomic prediction declined when genetic backgrounds were absent from training, and when leading predictive features differed among backgrounds. We also found that models trained on a curated list of mutations and variant effect predictors performed well when classifying drug-susceptible strains, but the drug-resistance trait was predicted with lower accuracy. These findings support the potential of genome-based resistance prediction while highlighting the need for broader population sampling, functional validation of candidate variants and expanded resistance catalogues to improve prediction across genetic backgrounds.

microbiology↗
bioRxiv2025

Epistasis at the cell surface: what is the role of Erg3 loss-of-function in acquired echinocandin resistance?

Echinocandins, which target the fungal {beta}-1,3-glucan synthase (Fks), are essential for treating invasive fungal infections, yet resistance is increasingly reported. While resistance typically arises through mutations in Fks hotspots, emerging evidence suggests a contributing role of changes in membrane sterol composition due to ERG3 mutations. Here, we present a clinical case of Nakaseomyces glabratus (Candida glabrata) in which combined mutations in ERG3 and FKS2, but not FKS2 alone, appear to confer echinocandin resistance. Integrated analyses reveal a recurrent association between Erg3 loss-of-function and echinocandin resistance mediated by Fks variation across Candida species, but exclude ERG3 loss-of-function as an independent resistance mechanism. Advances in Fks structural biology and insights into echinocandin-Fks interactions support a model of epistatic crosstalk between membrane sterols and Fks function. Understanding this interaction is crucial, as it may underlie not only acquired echinocandin resistance but also the broader development of multidrug resistance across major antifungal drug classes.

molecular biology↗
bioRxiv2025

The effect of allelic molecular interactions on phenotypic dominance

Mendelian genetics provides us with a framework for studying allelic dominance relationships at a locus at the phenotypic level. These dominance relationships result from different molecular factors, including the mapping of molecular activity onto fitness. For homomeric proteins, physical interactions between alleles provide a mechanism by which one allele can have a dominant effect on the activity of the other. Here, we refer to the effect of these interactions as molecular dominance and examine how they determine total protein activity and contribute to phenotypic dominance. The relative impact of such molecular dominance effects depends on the proportion of subunits that heteromerize relative to those that form homomers. In turn, we show how the effect of physical interactions on phenotypic dominance depends on the function linking protein activity to fitness. Our results show the complex relationships between molecular and phenotypic dominance and highlight the fundamental difference in dominance landscapes for monomeric and homomeric proteins.

genetics↗
bioRxiv2025

Co-translational assembly promotes functional diversification of paralogous proteins

Homomeric proteins are ubiquitous and mediate myriads of cellular functions. When a gene encoding a homomer duplicates, the resulting paralogs can either form distinct homomers, or evolve into a heteromer containing both paralogs. While such events have extensively shaped proteomes, the molecular mechanisms driving these fates and their associated functional consequences remain largely unknown. Here, we conducted a comprehensive phylogenomic analysis tracing gene duplication histories of 7,377 human paralogs across the eukaryotic lineage and identified their fates using protein interaction data. Simulations and data analyses show that cellular constraints must act as barriers to disfavor heteromerization and promote homomerization. We found that multiple cellular and molecular constraints can serve as barriers, including the lack of co-expression and co-localization. The main barrier, however, is co-translational assembly, which naturally promotes the self-assembly of each paralog from its corresponding mRNA, thus hindering heteromerization. We further established that heteromerization constrains functional divergence, with homomeric paralogs exhibiting stronger signatures of adaptive evolution and functional divergence compared to heteromeric paralogs. Together, these findings identify key biochemical and cellular properties that explain protein function diversification following gene duplication. One Sentence SummaryCo-translational assembly drives the selective homo-oligomerization of paralogs, which in turn promotes their functional divergence. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=180 HEIGHT=200 SRC="FIGDIR/small/634331v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@b17418org.highwire.dtl.DTLVardef@3d0a61org.highwire.dtl.DTLVardef@1747aeaorg.highwire.dtl.DTLVardef@31b931_HPS_FORMAT_FIGEXP M_FIG C_FIG

evolutionary biology↗
bioRxiv2024

FungAMR: A comprehensive portrait of antimicrobial resistance mutations in fungi

Antimicrobial resistance (AMR) is a global threat. To optimize the use of our antifungal arsenal, we need rapid detection and monitoring tools that rely on high-quality AMR mutation data. Here, we performed a thorough manual curation of published AMR mutations in fungal pathogens to produce the FungAMR reference dataset. A total of 501 papers were curated, leading to 35,792 mutation entries all classified with the degree of evidence that supports their role in resistance. FungAMR covers 95 species, 246 genes and 208 drugs. We combined variant effect predictors with FungAMR resistance mutations and showed that these tools could be used to help predict the potential impact of mutations on AMR. Additionally, a comparative analysis among species revealed a high level of convergence in the molecular basis of resistance, highlighting some potentially universal resistance mutations. The analysis also showed that a significant number of resistance mutations lead to cross-resistance within antifungals of a class, as well as between classes for certain mutated genes. The acquisition of fungal resistance in the clinic and the field is an urging concern. Finally, we provide a computational tool, ChroQueTas, that leverages FungAMR to screen fungal genomes for AMR mutations. These resources are anticipated to have great utility for researchers in the fight against antifungal resistance.

microbiology↗
bioRxiv2024

A role for the putative error-prone polymerase REV1 in DNA damage and antifungal drug resistance in Candida albicans

Antimicrobial-induced DNA damage, and subsequent repair via upregulation of DNA repair factors, including error-prone translesion polymerases, can lead to the increased accumulation of mutations in the microbial genome, and ultimately increased risk of acquired mutations associated with antimicrobial resistance. While this phenotype is well described in bacterial species, it is less thoroughly investigated amongst microbial fungi. Here, we monitor DNA damage induced by antifungal agents in the fungal pathogen Candida albicans, and find that commonly used antifungal drugs are able to induce DNA damage, leading to the upregulation of transcripts encoding predicted error-prone polymerases and related factors. We focus on REV1, encoding a putative error-prone polymerase, and find that while deleting this gene in C. albicans leads to increased sensitivity to DNA damage, it also unexpectedly renders cells more likely to incur mutations and evolve resistance to antifungal agents. We further find that deletion of REV1 leads to a significant depletion in the uncharacterized protein Shm1, which itself plays a role in fungal mutagenesis. Together, this work lends new insight into previously uncharacterized factors with important roles in the DNA damage response, mutagenesis, and the evolution of antifungal drug resistance.

microbiology↗
bioRxiv2024

Cryptic genetic variation shapes the fate of gene duplicates in a protein interaction network

Paralogous genes are often redundant for long periods of time before they diverge in function. While their functions are preserved, paralogous proteins can accumulate mutations that, through epistasis, could impact their fate in the future. By quantifying the impact of all single-amino acid substitutions on the binding of two myosin proteins to their interaction partners, we find that the future evolution of these proteins is highly contingent on their regulatory divergence and the mutations that have silently accumulated in their protein binding domains. Differences in the promoter strength of the two paralogs amplify the impact of mutations on binding in the lowly expressed one. While some mutations would be sufficient to non-functionalize one paralog, they would have minimal impact on the other. Our results reveal how functionally equivalent protein domains could be destined to specific fates by regulatory and cryptic coding sequence changes that currently have little to no functional impact.

evolutionary biology↗
bioRxiv2023

Hybrid adaptation is hampered by Haldane's sieve

Hybrids between species exhibit plastic genomic architectures that foster phenotypic diversity. Their genomic instability also incurs costs, potentially limiting adaptation. When challenged to evolve in an environment containing a UV mimetic drug, yeast hybrids have reduced adaptation rates compared to parents. We hypothesized that this reduction could result from a faster accumulation of genomic changes, but we found no such association. Alternatively, we proposed that hybrids might lack access to adaptive mutations occurring in the parents, yet, we identified mutations in the same genes (PDR1 and YRR1), suggesting similar molecular adaptation mechanisms. However, mutations in these genes tended to be homozygous in the parents but heterozygous in the hybrids. We hypothesized that a lower rate of loss of heterozygosity (LOH) in hybrids could limit fitness gain. Using genome editing, we demonstrated that mutations display incomplete dominance, requiring homozygosity to show full impact and to circumvent Haldanes sieve, which favors the fixation of dominant mutations. We used frozen fossils to track genotype frequency dynamics and confirmed that LOH occurs at a slower pace in hybrids than in parents. Together, these findings show that Haldanes sieve slows down adaptation in hybrids, revealing an intrinsic constraint of hybrid genomic architecture that can limit the role of hybridization in adaptive evolution.

evolutionary biology↗
bioRxiv2023

The substrate quality of CK2 target sites has a determinant role on their function and evolution

Most biological processes are regulated by peptide-recognition modules (PRMs) that bind to short linear motifs (SLiMs). Such interactions are rapidly reversible and often occur at low affinity. The protein kinase domain represents one such binding module, and known substrates may have full or only partial matches to the kinase recognition motif, a property known as substrate quality. However, it is not yet clear whether differences in substrate quality represent neutral variation along the phosphosite sequence or if these differences have functional consequences that are subject to selection. We explore this question in detail for the acidophilic kinase CK2. CK2 is well-characterised, clinically important, and a fundamental enzyme for many aspects of cell biology. We show that optimal CK2 sites are phosphorylated at maximal stoichiometries and found in many conditions whereas minimal substrates are phosphorylated at lower stoichiometries, are more dynamic during the cell cycle, and have regulatory functions. Optimal CK2 sites also tend to be older and more conserved than minimal sites, and evolutionary simulations indicate that the substrate quality of CK2 phosphosites is often tuned by selection. For intermediate target sites, increases or decreases to substrate quality may be deleterious, which we demonstrate experimentally for a CK2 substrate at the kinetochore. The results together suggest that minimal and optimal phosphosites are strongly differentiated in terms of their functional and evolutionary properties.

evolutionary biology↗
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

Exit of spore dormancy transforms the yeast cytoplasm and the solubility of its proteome

The biophysical properties of the cytoplasm are major determinants of key cellular processes and adaptation. Many yeasts produce dormant spores that can withstand extreme conditions. We show that spores of Saccharomyces cerevisiae exhibit extraordinary biophysical properties, including a highly viscous and acidic cytosol. These conditions alter the solubility of more than 100 proteins such as metabolic enzymes that become more soluble as spores transit to active cell proliferation upon nutrient repletion. A key regulator of this transition is the heat shock protein Hsp42, which shows transient solubilization and phosphorylation, and is essential for the transformation of the cytoplasm during germination. Germinating spores therefore return to growth through the dissolution of protein assemblies, orchestrated in part by Hsp42 activity. The modulation of spores molecular properties are likely key adaptive features of their exceptional survival capacities.

cell biology↗
bioRxiv2022

Behavioral Evidence for Enhanced Olfactory and Trigeminal Perception in Congenitally Deaf Individuals

Sensory deprivation, particularly hearing loss, is an excellent model to study neuroplasticity in the human brain and the adaptive behaviors that support the daily lives of deprived individuals. In adaptation to their hearing loss, deaf individuals rely on their other intact senses. Visual and tactile abilities are enhanced in deafness, but few studies have evaluated the olfactory function. This study aimed to compare the impact of congenital deafness on olfactory capacities using psychophysical tasks. Methodological issues raised in previous studies, such as homogeneous onset of deafness and cognitive function assessment, were considered. Eleven individuals with bilateral severe-to-profound deafness since birth were compared to 11 hearing non-signers similar in age (age range = 20-51 years old) and sex (7 women). The deaf subjects were assessed using various standardized neuropsychological tests to ascertain typical cognition. Olfactory functions were evaluated using the Sniffin Sticks battery test, which measures olfactory detection threshold, odor discrimination, and odor identification. Further, accuracy and response time were examined for the identification and localization of two odors to disentangle olfactory sensitivity from sensitivity in the trigeminal system. The Sniffin Sticks test demonstrated superior performances in the deaf participants to discriminate and identify odors. In line with this, they also showed higher sensitivity when both identifying and localizing odors. These findings suggest that congenital deafness is associated with superior performance in higher-level olfactory processing and increased sensitivity in the trigeminal system.

neuroscience↗
bioRxiv2020

The rate of whole-genome duplication can be accelerated by hybridization

Hybridization and polyploidization are powerful mechanisms of speciation. Hybrid speciation often coincides with whole-genome duplication (WGD) in eukaryotes. This suggests that WGD allows hybrids to thrive by restoring fertility and/or increasing access to adaptive mutations. Alternatively, it has been suggested that hybridization itself may trigger WGD. Testing these models requires quantifying the rate of WGD in hybrids without the confounding effect of natural selection. By measuring the spontaneous rate of WGD of 1304 yeast crosses evolved under relaxed selection, we show that some genotypes are more prone to WGD and WGD can be triggered by hybridization. We also find that higher WGD rate correlates with higher genomic instability and that WGD increases fertility and genetic variability. These results provide evidence that hybridization itself can promote WGD, which in turn facilitates the evolution of hybrids.

evolutionary biology↗
bioRxiv2020

Interspecific Hybrids Show a Reduced Adaptive Potential Under DNA Damaging Conditions

Hybridization may increase the probability of adaptation to extreme stresses. This advantage could be caused by an increased genome plasticity in hybrids, which could accelerate the search for adaptive mutations. High ultraviolet (UV) radiation is a particular challenge in terms of adaptation because it affects the viability of organisms by directly damaging DNA, while also challenging future generations by increasing mutation rate. Here we test if hybridization accelerates adaptive evolution in response to DNA damage, using yeast as a model. We exposed 180 populations of hybrids between species (Saccharomyces cerevisiae and Saccharomyces paradoxus) and their parental strains to UV mimetic and control conditions for approximately 100 generations. Although we found that adaptation occurs in both hybrids and parents, hybrids achieved a lower rate of adaptation, contrary to our expectations. Adaptation to DNA damage conditions comes with a large and similar cost for parents and hybrids, suggesting that this cost is not responsible for the lower adaptability of hybrids. We suggest that the lower adaptive potential of hybrids in this condition may result from the interaction between DNA damage and the inherent genetic instability of hybrids.Competing Interest StatementThe authors have declared no competing interest.View Full Text

ecology↗
bioRxiv2020

The genome sequence of the Jean-Talon strain, an archeological tetraploid beer yeast from Quebec

The genome sequences of archeological yeast isolates can reveal insights about the history of human baking, brewing and winemaking activities and migration around the globe. A yeast strain called Jean-Talon was recently isolated from the vaults of the Intendants Palace of Nouvelle France on a historical site in Quebec City. This site has been occupied by various breweries, starting from the end of the 17th century and until the middle of the 20th century. We sequenced the genome of the Jean-Talon strain with short and long reads and reanalyzed the genomes of hundreds of yeast strains to identify its species of origin and determine how it relates to other domesticated and wild strains. The Jean-Talon strain is a tetraploid strain with numerous aneuploidies, is partially sterile and most closely related to beer strains from the beer and bakery genetic groups and industrial strains from the United Kingdom and Belgium. We conclude from this that the Jean-Talon strain most likely derives from recent brewing activities that took place in the same location and not from wild yeast that could have been domesticated by the original brewers of the Nouvelle France on the site.

genomics↗
bioRxiv2020

The parasite Schistocephalus solidus secretes proteins with putative host manipulation functions

BackgroundManipulative parasites are thought to liberate molecules in their external environment acting as manipulation factors with biological functions implicated in their hosts physiological and behavioural alterations. These manipulation factors are part of a complex mixture called the secretome. While the secretomes of various parasites have been described, there is very little data for a putative manipulative parasite. It is necessary to study the molecular interaction between a manipulative parasite and its host to better understand how such alterations evolve. MethodsHere, we used proteomics to characterize the secretome of a model cestode with a complex life cycle based on trophic transmission. We studied Schistocephalus solidus during the life stage in which behavioural changes take place in its obligatory intermediate fish host, the threespine stickleback (Gasterosteus aculeatus). We produced a novel genome sequence and assembly of S. solidus to improve protein coding gene prediction and annotation for this parasite. We then described the whole worms proteome and its secretome during fish host infection using LC-MS/MS. ResultsA total of 2 290 proteins were detected in the proteome of S. solidus, and 30 additional proteins were detected specifically in the secretome. We found that the secretome contains proteases, proteins with neural and immune functions, as well as proteins involved in cell communication. We detected Receptor-type tyrosine-protein phosphatases, which were reported in other parasitic systems to be manipulation factors. We also detected 12 S. solidus-specific proteins in the secretome that may play important roles in host-parasite interactions. ConclusionsOur results suggest that S. solidus liberates molecules with putative host manipulation functions in the host and that many of them are species specific.

genomics↗
bioRxiv2019

The BUBR1 pseudokinase domain promotes efficient kinetochore PP2A-B56 recruitment to regulate spindle checkpoint silencing and chromosome alignment

The balance of phospho-signalling at outer-kinetochores during mitosis is critical for the accurate attachments between kinetochores and the mitotic spindle and timely exit from mitosis. In humans, a major player in determining this balance is the PP2A-B56 phosphatase which is recruited to the Kinase Attachment Regulatory Domain (KARD) of the Spindle Assembly Checkpoint protein Budding Uninhibited by Benzimidazole 1-related 1 (BUBR1) in a phospho-dependent manner. This event unleashes a rapid, switch-like phosphatase relay that reverses phosphorylation at the kinetochore, extinguishing the checkpoint and promoting anaphase entry. Here, we conclusively demonstrate that the pseudokinase domain of human BUBR1 lacks phosphotransfer activity and that it was maintained in vertebrates because it allosterically promotes KARD phosphorylation. Mutation or removal of this domain results in decreased PP2A-B56 recruitment to the outer kinetochore, attenuated checkpoint silencing and errors in chromosome alignment as a result of imbalance in Aurora B activity. We demonstrate that the functions of the BUBR1 pseudokinase and the BUB1 kinase domains are intertwined, providing an explanation for retention of the pseudokinase domain in certain eukaryotes.

cell biology↗
bioRxiv2019

The role of structural pleiotropy and regulatory evolution in the retention of heteromers of paralogs

Many paralogs derive from the duplication of genes encoding homomeric proteins. Such duplication events lead to the formation of homomers and heteromers, thus creating new structures from a single event. We exhaustively characterize this phenomenon using the budding yeast protein-protein interaction network. We observe that paralogs that heteromerize are very frequent and less functionally diverged than those that lost this property, raising the possibility that heteromerization prevents functional divergence. Using in silico evolution, we show that for homomers and heteromers that share binding interfaces, mutations on one complex have pleiotropic effects on the other complex, resulting in highly correlated responses to selection. As a result, heteromerization could be preserved indirectly due to selection for the maintenance of homomers. By integrating data on gene expression and protein localization, we find that regulatory evolution could play a role in overcoming these structural pleiotropic effects and in allowing paralog functional divergence.

evolutionary biology↗