Recombinant Saccharomyces cerevisiae Putative uncharacterized protein YGR265W (YGR265W)

What is YGR265W and why is it classified as a "putative uncharacterized protein"?

YGR265W is a gene locus in Saccharomyces cerevisiae that encodes a protein whose biological function has not been experimentally validated. The term "putative" indicates it has been computationally predicted to encode a protein, while "uncharacterized" signifies that its biological role, biochemical properties, and structural features remain largely unknown. According to the Saccharomyces Genome Database, there is no expression data available for YGR265W, further reflecting its uncharacterized status .

Which expression systems are recommended for studying recombinant proteins like YGR265W in S. cerevisiae?

The pYES vector collection is specifically designed for high-level expression of recombinant proteins in S. cerevisiae, making it ideal for expressing proteins like YGR265W. These vectors offer:

• Regulated expression via the GAL1 promoter for controlled induction

• Multiple vector options with varying origins of replication for different expression levels

• Several cloning technologies including TOPO® Cloning and Gateway™ Technology

The key vector types include:

• pYES2.1/V5-His TOPO® (5.9 kb) - Features 2μ origin for high-copy maintenance and URA3 selection

• pYES-DEST52 (7.8 kb) - Combines Gateway™ technology with GAL1 regulation

• pYES2/CT and pYES3/CT - Offer URA3 and TRP1 selection markers respectively

• pYES6/CT - Contains Blasticidin resistance for selection in any strain regardless of auxotrophic markers

For proteins that may be toxic when highly expressed, pYC vectors containing the CEN6/ARSH4 origin provide lower copy numbers within yeast cells .

How can I detect and verify expression of YGR265W in yeast?

To verify successful expression of YGR265W, utilize the epitope tags engineered into the pYES vectors:

Detection methods:

• Western blotting: Using antibodies against the vector-provided tags:

  • V5 epitope and polyhistidine tags in pYES2.1/V5-His

  • XpressTM-6xHis tag in pYC2/NT

  • V5-His tags in pYC2/CT and pYC6/CT

• Affinity purification: His-tagged proteins can be purified using nickel columns, allowing for:

  • Quantification of expression levels

  • Assessment of protein solubility

  • Further characterization studies

• Cellular localization: Fluorescence microscopy using antibodies against epitope tags or GFP fusion constructs to determine subcellular distribution

• Mass spectrometry: For confirmatory identification and potential post-translational modification analysis

What are the optimal conditions for inducing recombinant protein expression using the pYES system?

The GAL1 promoter in pYES vectors provides tight regulation of expression through carbon source manipulation:

Induction protocol:

• Grow transformed yeast in glucose-containing medium to desired density (glucose represses the GAL1 promoter)

• Harvest cells by centrifugation and wash thoroughly to remove residual glucose

• Resuspend in media containing galactose as carbon source to induce expression

• Incubate at appropriate temperature (typically 30°C for standard growth, but 20-25°C may improve folding)

• Monitor expression at multiple time points (4, 8, 12, 24 hours) to determine optimal induction time

Key considerations:

• Transcription from the GAL1 promoter is repressed by glucose and induced by galactose

• Lower temperatures during induction often improve folding and solubility

• Expression levels may vary depending on the specific protein and strain background

How can I successfully transform S. cerevisiae with YGR265W expression constructs?

For efficient yeast transformation with YGR265W expression constructs:

Recommended method:
The S.c. EasyComp™ Transformation Kit offers advantages over traditional methods:

• Preparation of competent cells takes less than 30 minutes

• Uses ready-to-use, quality-tested solutions

• More efficient than spheroplast formation and traditional LiCl methods

Protocol overview:

• Grow yeast culture to log phase (OD600 = 0.6-0.8)

• Prepare competent cells using kit solutions

• Mix competent cells with plasmid DNA and transformation solution

• Heat shock at 42°C for 1 hour

• Plate on selective media appropriate for the vector's selection marker:

  • SC-URA for pYES2/CT and pYC2/CT (URA3 marker)

  • SC-TRP for pYES3/CT (TRP1 marker)

  • YPD + Blasticidin for pYES6/CT and pYC6/CT (Blasticidin resistance)

What functional genomics approaches can reveal the biological role of uncharacterized proteins like YGR265W?

Uncovering the function of YGR265W requires a multi-faceted approach:

Computational strategies:

• Sequence analysis:

  • Homology searches across species

  • Protein domain and motif identification

  • Structural prediction using tools like AlphaFold

• Network analysis:

  • Co-expression patterns with characterized genes

  • Integration with protein-protein interaction data

  • Metabolic pathway association analysis

Experimental strategies:

• Gene disruption approaches:

  • CRISPR-Cas9 knockout

  • Conditional degradation systems

  • Dominant negative mutations

• Phenotypic assays:

  • Growth under various conditions (temperature, carbon sources, stress)

  • Cellular morphology analysis

  • Metabolite profiling

• Protein-level studies:

  • Localization determination

  • Interaction partner identification

  • Post-translational modification analysis

Being systematic in this approach is critical, as seen in studies of other uncharacterized yeast proteins like those in the ORF collections analyzed with neural network methods .

How can I design experiments to determine if the SynII phenotypic defect at 37°C on YPG media is related to YGR265W?

To investigate potential connections between YGR265W and the observed SynII phenotypic defect at 37°C on YPG media:

Experimental design:

• Complementation analysis:

  • Transform SynII strain with wild-type YGR265W expressed from a plasmid

  • Assess rescue of growth defect at 37°C on YPG media

  • Include appropriate controls (empty vector, unrelated gene)

• Expression analysis:

  • Compare YGR265W expression levels between wild-type and SynII strains

  • Perform qRT-PCR and western blotting at various temperatures

  • Analyze results for expression differences that correlate with phenotype

• Targeted mutagenesis:

  • Generate specific mutations in YGR265W

  • Analyze which domains/residues are critical for function

  • Test mutants for ability to complement the 37°C YPG defect

Data collection and analysis:

This approach follows the methodology demonstrated in previous research where the SynII defect at 37°C on YPG media was successfully rescued by complementing with a wild-type gene .

What strategies can optimize YGR265W expression when facing solubility or toxicity challenges?

When facing expression challenges with YGR265W:

For toxicity issues:

• Vector selection:

  • Switch from pYES vectors (2μ origin, high-copy) to pYC vectors (CEN6/ARSH4 origin, low-copy)

  • This reduces copy number and expression levels, minimizing potential toxic effects

• Induction optimization:

  • Use lower galactose concentrations for partial induction

  • Reduce induction temperature to 20-25°C

  • Shorten induction time

For solubility issues:

• Fusion tag strategies:

  • Add solubility-enhancing tags (MBP, GST, SUMO)

  • Include fusion proteases for tag removal

  • Position tags at either N- or C-terminus to determine optimal configuration

• Expression conditions:

  • Screen multiple growth media formulations

  • Test various induction temperatures (16°C, 20°C, 25°C, 30°C)

  • Optimize induction duration through time-course analysis

• Co-expression approaches:

  • Co-express molecular chaperones to aid folding

  • Include pathway partners that may stabilize YGR265W

Optimization matrix:

How can advanced bioinformatic approaches predict potential functions of YGR265W?

To predict functions of YGR265W using bioinformatic approaches:

Sequence-based analysis:

• Homology detection:

  • Position-Specific Iterative BLAST (PSI-BLAST) against multiple databases

  • Hidden Markov Model (HMM) profiling for remote homology detection

  • Sensitive sequence comparison tools (HHpred, HMMER)

• Evolutionary analysis:

  • Conservation patterns across fungal species

  • Synteny analysis of genomic context

  • Detection of co-evolving residues suggesting functional sites

Structure-based prediction:

• Structural modeling:

  • Generate 3D models using AlphaFold2

  • Assess model confidence using prediction metrics

  • Identify structural similarities with characterized proteins

• Functional site prediction:

  • Identify potential binding pockets and catalytic sites

  • Predict protein-protein interaction interfaces

  • Analyze electrostatic and hydrophobic surface properties

Integrated approaches:

• Multi-feature machine learning:

  • Train neural network models using multiple feature types

  • Apply methods similar to those used for predicting protein coding regions

  • Integrate heterogeneous data types (sequence, structure, expression)

• Pathway and network analysis:

  • Analyze co-expression patterns

  • Examine genetic interaction profiles

  • Study metabolic network positioning

What experimental approaches can identify protein-protein interactions involving YGR265W?

To systematically identify and validate protein interactions of YGR265W:

Unbiased screening methods:

• Yeast two-hybrid (Y2H):

  • Clone YGR265W into bait vector

  • Screen against genome-wide prey library

  • Filter results based on reporter activation strength

  • Verify interactions through secondary assays

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

  • Express tagged YGR265W using pYES vectors with C-terminal V5-His tags

  • Perform immunoprecipitation under native conditions

  • Identify co-purifying proteins by LC-MS/MS

  • Quantify enrichment versus controls

• Proximity-based labeling:

  • Create fusion of YGR265W with BioID or APEX2

  • Express in yeast using inducible GAL1 promoter

  • Perform proximity labeling in vivo

  • Identify biotinylated proteins by streptavidin purification and MS

Validation approaches:

• Co-immunoprecipitation:

  • Reciprocal tagging of candidate interactors

  • Western blot analysis of co-precipitated proteins

  • Competition assays to test interaction specificity

• Bimolecular fluorescence complementation (BiFC):

  • Create split-fluorescent protein fusions

  • Visualize interactions in living cells

  • Quantify interaction strength through fluorescence intensity

Interaction network analysis:

How can I design CRISPR-Cas9 experiments to study YGR265W function in vivo?

For genetic manipulation of YGR265W using CRISPR-Cas9:

Gene knockout strategy:

• Guide RNA design:

  • Design sgRNAs targeting the 5' and 3' regions of YGR265W

  • Ensure specificity using genome-wide off-target prediction tools

  • Synthesize or clone sgRNAs into appropriate vectors

• Repair template preparation:

  • Design homology arms (40-60 bp) flanking the YGR265W locus

  • Include selection marker (e.g., KanMX) between homology arms

  • Verify template integrity by sequencing

• Delivery and screening:

  • Transform yeast with Cas9, sgRNA, and repair template

  • Select transformants on appropriate media

  • Verify deletion by PCR and sequencing

  • Perform phenotypic characterization under various conditions

Precise editing applications:

• Domain analysis:

  • Introduce specific mutations in predicted functional domains

  • Create truncation variants to map essential regions

  • Engineer chimeric proteins to test domain function

• Tagging strategies:

  • Add fluorescent proteins for localization studies

  • Insert epitope tags for immunoprecipitation

  • Create degron fusions for conditional depletion

• Promoter engineering:

  • Replace native promoter with regulatable alternatives

  • Create reporter fusions to study expression patterns

  • Implement CRISPR interference for tunable repression

Phenotypic analysis framework:

This approach allows for comprehensive functional characterization of YGR265W through precise genetic manipulation.

What approaches can characterize the biochemical properties of purified recombinant YGR265W?

To biochemically characterize purified recombinant YGR265W:

Expression and purification strategy:

• Vector selection:

  • Use pYES2.1/V5-His TOPO® for high-level expression with C-terminal tags

  • Consider pYC vectors if toxicity is observed

• Purification approach:

  • Lyse cells under optimized conditions (mechanical disruption, detergents)

  • Perform immobilized metal affinity chromatography using His-tag

  • Apply secondary purification (ion exchange, size exclusion)

  • Verify purity by SDS-PAGE and mass spectrometry

Biochemical characterization:

• Structural studies:

  • Circular dichroism spectroscopy for secondary structure

  • Thermal shift assays for stability assessment

  • Limited proteolysis to identify stable domains

  • X-ray crystallography or cryo-EM for high-resolution structure

• Functional assays:

  • Enzymatic activity screening against substrate libraries

  • Binding assays using label-free techniques (ITC, SPR, BLI)

  • Mass spectrometry to identify post-translational modifications

  • Oligomerization state determination by analytical ultracentrifugation

Data integration table:

How can multi-omics approaches integrate transcriptomic, proteomic, and metabolomic data to understand YGR265W function?

To comprehensively investigate YGR265W function using multi-omics:

Experimental design:

• Generate experimental system:

  • Create YGR265W deletion strain

  • Develop controlled overexpression using GAL1 promoter

  • Include appropriate wild-type controls

• Multi-omics data collection:

  • Transcriptomics: RNA-seq under multiple conditions

  • Proteomics: Quantitative MS (SILAC, TMT)

  • Metabolomics: Targeted and untargeted approaches

  • Interactomics: AP-MS or proximity labeling

  • Phenomics: High-throughput phenotypic assays

Data integration and analysis:

• Correlation analysis:

  • Identify genes/proteins with expression patterns correlated with YGR265W

  • Map transcriptional and translational responses to YGR265W perturbation

  • Correlate metabolite changes with pathway alterations

• Network reconstruction:

  • Build gene regulatory networks

  • Construct protein-protein interaction networks

  • Map metabolic pathway alterations

  • Integrate networks across multiple data types

• Functional prediction:

  • Apply machine learning for function prediction

  • Use clustering to identify functional groups

  • Perform enrichment analysis for biological processes

Integration framework:

This multi-dimensional approach provides a comprehensive understanding of YGR265W function by capturing its impact across multiple levels of cellular organization.