Recombinant Saccharomyces cerevisiae Putative uncharacterized protein YOR218C (YOR218C)

What is known about the structure and localization of YOR218C in Saccharomyces cerevisiae?

YOR218C is a putative uncharacterized protein in Saccharomyces cerevisiae with limited direct characterization. For structure prediction, sequence architecture analysis tools like ANNOTATOR can reveal features such as intrinsically unstructured regions and repeat domains, similar to analyses performed for other uncharacterized yeast proteins like YBR238C . For YBR238C, such analysis revealed an intrinsically unstructured region over the first ~130 residues followed by a pentatricopeptide repeat region, providing clues to its potential RNA-binding function .

For localization studies, fluorescent protein tagging methods provide the most reliable results:

• Create C-terminal or N-terminal GFP fusions using PCR-based methods

• Verify correct integration by PCR and sequencing

• Use confocal microscopy with appropriate organellar markers

• Confirm localization using subcellular fractionation and Western blot

Similar uncharacterized yeast proteins like YBR238C have been identified with mitochondrial localization, which provided critical insight into their function . The subcellular localization of YOR218C would similarly provide important clues to its potential cellular role.

How can I design a robust experimental approach to verify YOR218C expression under different growth conditions?

To verify YOR218C expression across different conditions, a multi-method approach is recommended:

• qRT-PCR analysis: Design primers specific to YOR218C with appropriate reference genes (ACT1, ALG9, TAF10) for normalization. This approach has been successfully used for confirming expression of other uncharacterized genes like YBR238C in different yeast backgrounds .

• Western blot analysis: Generate antibodies against YOR218C or use epitope tagging methods (HA, FLAG) followed by detection with commercial antibodies.

• RNA-seq analysis: For genome-wide expression profiling, compare YOR218C expression across different conditions.

A comprehensive experimental design should include multiple growth conditions:

This multi-faceted approach allows for detecting condition-specific regulation patterns that might provide functional insights, as demonstrated in the study of YBR238C where rapamycin treatment was found to significantly downregulate expression .

What are the most reliable methods to generate and verify a YOR218C deletion strain?

For generating a reliable YOR218C deletion strain, consider these methodological approaches:

• PCR-based gene deletion: Use homologous recombination with selection markers (KanMX, HIS3, URA3). This method has been effectively used for generating deletion strains of other uncharacterized genes like YBR238C .

• CRISPR-Cas9 based deletion: For increased efficiency, especially in strains with low homologous recombination rates.

Key verification steps include:

• Design primers with 40-50bp homology to the regions flanking YOR218C

• Verify deletion by PCR from both ends of the integration site

• Confirm absence of YOR218C expression by RT-PCR

• Generate the deletion in multiple strain backgrounds to account for genetic background effects

• Create a complementation strain by reintroducing YOR218C under its native promoter

For studies of YBR238C, researchers confirmed deletion through multiple verification methods and tested the mutant in different strain backgrounds (BY4743 and CEN.PK) to ensure reproducibility of phenotypes . This approach is critical as strain background can significantly influence gene deletion phenotypes.

What experimental design is most appropriate for determining the function of YOR218C?

A comprehensive experimental design to determine YOR218C function should include:

• Phenotypic screening: Test YOR218C deletion and overexpression strains under various conditions:

  • Different carbon sources and nutrients

  • Temperature stress (heat shock, cold shock)

  • Oxidative stress (H₂O₂, paraquat)

  • DNA damage agents (UV, MMS)

  • Cell wall/membrane stress (Congo red, SDS)

• Transcriptomic analysis: Compare gene expression profiles between wild-type and mutant strains:

  • RNA-seq or microarray analysis

  • Identify differentially expressed genes

  • Perform pathway enrichment analysis

  • Validate key genes by qRT-PCR

• Genetic interaction screening:

  • Synthetic genetic array (SGA) analysis

  • Identify suppressors and enhancers

• Functional assays based on localization:

  • If mitochondrial: measure oxygen consumption, membrane potential

  • If nuclear: analyze DNA binding using ChIP

  • If cytoplasmic: examine interaction with cytoskeleton or translation machinery

For YBR238C, a combination of transcriptome analysis and phenotypic assays revealed its role in mitochondrial function and cellular aging, which would not have been evident from a single approach . The transcriptome analysis of YBR238C deletion mutant identified 326 upregulated and 61 downregulated genes, with significant enrichment in mitochondrial function pathways .

How should I design a transcriptome analysis experiment to study the effects of YOR218C deletion?

For robust transcriptome analysis of YOR218C deletion effects:

• Experimental design:

  • Compare at least 3-4 biological replicates of wild-type and YOR218C deletion strains

  • Include YOR218C overexpression strain if possible

  • Consider time-course analysis if studying dynamic processes

  • Grow cells under standardized conditions

• RNA isolation and quality control:

  • Use methods optimized for yeast (hot phenol or commercial kits)

  • Verify RNA integrity using Bioanalyzer (RIN > 8)

  • Prepare samples simultaneously to minimize batch effects

• Sequencing considerations:

  • Aim for 20-30 million reads per sample

  • Use paired-end sequencing for better transcript identification

  • Include spike-in controls for normalization

• Data analysis pipeline:

• Validation:

  • Confirm key differentially expressed genes by qRT-PCR

  • Perform protein-level validation for selected targets

A well-designed transcriptome analysis, as demonstrated in YBR238C studies, can reveal unexpected pathways and functional associations that guide further targeted experiments .

How can I determine if YOR218C affects cellular lifespan in yeast?

To determine if YOR218C affects cellular lifespan in yeast, employ both chronological lifespan (CLS) and replicative lifespan (RLS) assays:

• Chronological Lifespan (CLS) Analysis:

  • Grow wild-type and YOR218C deletion strains to stationary phase

  • Maintain cultures without additional nutrients

  • Sample at regular intervals (e.g., days 1, 3, 5, 7, 10, 14, 21)

  • Determine viability using multiple methods:
    a) Colony forming unit (CFU) counts
    b) Outgrowth in liquid media (OD-based)
    c) Vital dye staining (e.g., FUN-1, propidium iodide)

• Replicative Lifespan (RLS) Analysis:

  • Use micromanipulation to track individual mother cells

  • Count total buds produced before senescence

  • Analyze minimum 40-50 cells per strain

• Molecular Markers of Aging:

  • Measure ROS levels using fluorescent dyes

  • Assess mitochondrial membrane potential

  • Quantify damaged/aggregated proteins

  • Evaluate stress resistance

For YBR238C, researchers used three different outgrowth survival methods to confirm its role in CLS . The deletion increased CLS compared to wild-type cells, which correlated with enhanced mitochondrial function and reduced ROS levels .

How can I investigate potential interactions between YOR218C and cellular signaling pathways?

To investigate interactions between YOR218C and cellular signaling pathways:

• Genetic interaction screening:

  • Cross YOR218C deletion with deletions of key signaling pathway components

  • Look for synthetic growth defects or suppression

  • Perform focused epistasis analysis with key pathway members

• Phosphoproteomic analysis:

  • Compare phosphorylation profiles between wild-type and YOR218C mutants

  • Identify differentially phosphorylated proteins in signaling pathways

  • Use kinase inhibitors to validate pathway connections

• Transcriptional reporter assays:

  • Use pathway-specific transcriptional reporters

  • Compare reporter activity in presence/absence of YOR218C

  • Test response to pathway activators and inhibitors

• Chemical genetic profiling:

  • Screen YOR218C mutants for altered sensitivity to pathway inhibitors

  • Use drug combinations to map pathway interactions

For YBR238C, researchers discovered connections to the TORC1 signaling pathway by observing its regulation by rapamycin . The study revealed that YBR238C is an effector of TORC1 that modulates mitochondrial function, establishing a feedback loop between TORC1 and mitochondria that regulates cellular aging processes .

This systematic approach can reveal unexpected signaling connections, as demonstrated by the discovery of YBR238C's role in the TORC1-mitochondria signaling axis .

What approaches can be used to identify protein-protein interactions involving YOR218C?

For identifying protein-protein interactions involving YOR218C:

• Affinity purification coupled with mass spectrometry (AP-MS):

  • Tag YOR218C with affinity tags (TAP, FLAG, HA)

  • Purify under native conditions to preserve interactions

  • Identify co-purifying proteins by mass spectrometry

  • Compare with control purifications to eliminate background

• Proximity-based labeling:

  • Fuse YOR218C to BioID, TurboID, or APEX2

  • Allow in vivo labeling of proximal proteins

  • Purify biotinylated proteins and identify by MS

  • Advantage: can detect transient interactions

• Yeast two-hybrid (Y2H) screening:

  • Use YOR218C as bait against prey libraries

  • Perform targeted Y2H with suspected interactors

  • Confirm interactions by co-immunoprecipitation

• In vitro binding assays:

  • Express recombinant YOR218C or domains

  • Perform pull-down assays with candidate interactors

  • Use protein microarrays for unbiased screening

For proteins like YBR238C and its paralog RMD9, which are involved in RNA binding, RNA immunoprecipitation followed by sequencing (RIP-seq) has also been valuable to identify RNA interaction partners .

How do I interpret contradictory results in YOR218C functional studies?

When facing contradictory results in YOR218C functional studies:

• Examine strain background differences:

  • Different yeast strains can show different phenotypes for the same gene deletion

  • Compare genetic backgrounds (e.g., S288C/BY vs. W303 vs. ∑1278b)

  • Reintroduce YOR218C in multiple backgrounds to test complementation

• Analyze experimental condition variations:

  • Growth medium differences (rich vs. minimal, carbon source)

  • Growth phase when samples were collected

  • Environmental factors (temperature, pH, aeration)

• Evaluate methodological differences:

  • Assay sensitivity and specificity

  • Time points selected for analysis

  • Sample preparation techniques

• Systematic resolution approach:

  • Reproduce conflicting results under identical conditions

  • Perform epistasis experiments with related genes

  • Use orthogonal methods to measure the same phenotype

  • Develop time-course experiments to capture dynamics

For context, YBR238C had conflicting annotations in SGD for both increased and decreased RLS upon deletion . This was resolved by careful examination of original studies, which revealed a database annotation error . Multiple independent studies actually confirmed increased lifespan upon deletion .

How can evolutionary conservation analysis help understand YOR218C function?

Evolutionary conservation analysis provides valuable insights into YOR218C function:

• Sequence conservation analysis:

  • Perform BLAST/HMM searches across fungal species

  • Identify orthologs in other organisms

  • Calculate conservation scores for different protein regions

  • Identify highly conserved domains or motifs

• Comparative genomics approaches:

  • Analyze synteny around YOR218C locus across species

  • Examine co-evolution with functionally related genes

  • Look for gene presence/absence patterns correlating with traits

• Structural conservation:

  • Predict protein structure using AlphaFold or similar tools

  • Compare structural conservation vs. sequence conservation

  • Identify structurally conserved regions that may be functionally important

• Functional complementation:

  • Test if orthologs from other species can complement YOR218C deletion

  • Swap conserved domains between orthologs to identify functional regions

For YBR238C, sequence architecture analysis revealed a pentatricopeptide repeat region with homology to a known structure (HHpred hit to structure 7A9X chain A with E-value 2.e−56), suggesting a potential RNA-binding function similar to its paralog RMD9 .

What controls are essential when studying phenotypic effects of YOR218C deletion or overexpression?

Essential controls for studying phenotypic effects of YOR218C manipulation:

• Strain-specific controls:

  • Wild-type parental strain (same genetic background)

  • Empty vector control for overexpression studies

  • Complementation strain (YOR218C deletion with reintroduced YOR218C gene)

  • Deletion/overexpression of a non-related gene

• Verification controls:

  • PCR verification of correct gene deletion

  • qRT-PCR or Western blot verification of expression levels

  • Growth curve analysis to ensure comparable growth rates

• Phenotype-specific controls:

  • Positive control strains with known phenotypes in the pathway of interest

  • Multiple independent measurements of each phenotype

  • Different methods to measure the same phenotype when possible

• Experimental design controls:

  • Randomized experimental order

  • Blind scoring of phenotypes when possible

  • Technical replicates (minimum 3)

  • Biological replicates (minimum 3 independent transformants)

In studies of YBR238C, critical controls included complementary approaches to measure lifespan (chronological and replicative), multiple outgrowth survival methods for CLS analysis, and testing in different strain backgrounds (BY4743 and CEN.PK) . This comprehensive control strategy helped establish the causal relationship between gene deletion and observed phenotypes.

What statistical approaches are most appropriate for analyzing phenotypic changes in YOR218C mutants?

For robust statistical analysis of phenotypic changes in YOR218C mutants:

• Experimental design considerations:

  • Power analysis to determine sample size

  • Randomization of experimental units

  • Blind scoring when possible

  • Include appropriate technical and biological replicates

• Growth rate analysis:

  • Fit growth curves to appropriate models (logistic, Gompertz)

  • Compare doubling times using t-tests or ANOVA

  • For competitive growth, use relative fitness calculations

• Survival analysis for lifespan studies:

  • Kaplan-Meier curves for survival data

  • Log-rank test for comparing survival distributions

  • Cox proportional hazards model for multi-factor analysis

• Gene expression analysis:

  • DESeq2 or edgeR for differential expression

  • Multiple testing correction (Benjamini-Hochberg)

  • GSEA or GO enrichment for pathway analysis

In studies of YBR238C, statistical significance in lifespan assays was determined using log-rank tests, while transcriptome data was analyzed using standard differential expression pipelines with FDR-corrected p-values .

How can I determine if observed effects of YOR218C manipulation are direct or indirect?

To distinguish between direct and indirect effects of YOR218C manipulation:

• Temporal analysis:

  • Use inducible systems (TET-OFF, GAL1 promoter) to control YOR218C expression

  • Monitor cellular responses at multiple time points after induction/repression

  • Early responses are more likely to be direct effects

• Dose-response relationships:

  • Create strains with varying levels of YOR218C expression

  • Correlate phenotype strength with expression level

  • Direct effects often show proportional relationships

• Biochemical interaction studies:

  • Perform ChIP (if DNA-binding) or RIP (if RNA-binding)

  • Use protein-protein interaction methods (Y2H, BioID, co-IP)

  • Direct physical interactions suggest direct functional relationships

• Genetic interaction analysis:

  • Epistasis analysis with genes in related pathways

  • Suppressor and enhancer screening

  • Synthetic genetic array (SGA) analysis

For YBR238C, researchers determined its relationship with HAP4 and mitochondrial function through multiple approaches, including epistasis analysis, which revealed both HAP4-dependent and HAP4-independent mechanisms of action .

What methods are most effective for studying YOR218C's potential role in stress response?

To study YOR218C's potential role in stress response:

• Survival assays under various stresses:

  • Compare wild-type, deletion, and overexpression strains under:

    • Oxidative stress (H₂O₂, menadione, paraquat)

    • Heat shock (37-42°C)

    • Osmotic stress (NaCl, sorbitol)

    • ER stress (tunicamycin, DTT)

    • DNA damage (UV, MMS, HU)

  • Measure survival by spot assays and growth curves

• Stress response pathway activation:

  • Monitor stress-responsive transcription factors:

    • Msn2/4 nuclear localization (general stress)

    • Yap1 nuclear localization (oxidative stress)

    • Hog1 phosphorylation (osmotic stress)

    • Hsf1 activity (heat shock)

  • Use reporter constructs (e.g., GFP under stress-responsive promoters)

• Cellular damage assessment:

  • Measure ROS levels (DCF-DA, DHE fluorescence)

  • Assess protein aggregation (Hsp104-GFP foci)

  • Monitor DNA damage (γ-H2AX, comet assay)

  • Evaluate membrane integrity (PI staining)

For YBR238C, researchers found it was involved in regulating oxidative stress response, with deletion mutants showing decreased ROS levels and increased resistance to H₂O₂-induced oxidative stress toxicity . They also identified that the stress response controlling transcription factor MSN4 is upregulated in YBR238C deletion mutants .

How should I design experiments to study potential paralogs and genetic interactions of YOR218C?

To study potential paralogs and genetic interactions of YOR218C:

• Paralog identification and analysis:

  • Use sequence homology searches to identify potential paralogs

  • Create single and double deletion mutants

  • Compare phenotypes between single and double mutants

  • Analyze cross-complementation by overexpressing one paralog in the deletion background of another

• Systematic genetic interaction screening:

  • Cross YOR218C deletion with genome-wide deletion collection

  • Score growth phenotypes to identify genetic interactions

  • Classify interactions as negative (synthetic sick/lethal) or positive (suppression)

  • Group interacting genes into functional clusters

• Targeted epistasis analysis:

  • Create double mutants with genes in suspected related pathways

  • Analyze phenotypes to determine pathway relationships

  • Design order-of-function experiments with inducible systems

For YBR238C, researchers identified RMD9 as a paralog sharing ~45% amino acid identity . Surprisingly, they found that RMD9 deletion has an effect opposite to YBR238C deletion on chronological lifespan . This highlights the importance of studying paralogs, as they may have diverged to perform opposing regulatory functions.