Recombinant Saccharomyces cerevisiae Putative uncharacterized protein YHR145C (YHR145C)

What is YHR145C and why is it classified as a putative uncharacterized protein?

YHR145C is one of the approximately 1000 uncharacterized genes in Saccharomyces cerevisiae that lack experimental evidence for a specific physiological function. The classification as "putative uncharacterized" indicates that while the gene exists and is predicted to encode a protein, substantial experimental evidence confirming its function remains insufficient. According to genomic studies, approximately 5% of genes classified as uncharacterized by SGD (Saccharomyces Genome Database) could actually be considered characterized by conventional standards . Many uncharacterized ORFs lack experimental evidence to support specific physiological functions or even functionality in general .
Methodological approach for characterization:

• Sequence analysis and comparative genomics against characterized proteins

• Predict protein domains and motifs through computational tools

• Assess expression patterns under various conditions

• Conduct phenotypic analysis of deletion mutants

• Perform protein localization studies

What experimental approaches should researchers prioritize for initial characterization of YHR145C?

Initial characterization should follow a systematic workflow combining computational prediction with experimental validation:

How does YHR145C compare to other uncharacterized yeast proteins?

Comparative analysis can provide valuable insights into the potential function of YHR145C. Many uncharacterized yeast proteins share similarities in sequence, expression patterns, or genetic interactions. For instance, of the uncharacterized ORFs in yeast, 161 have sequences at least 50% identical to the sequences of another uncharacterized protein . This suggests potential functional redundancy, which might explain why they have remained uncharacterized through conventional single-gene analyses.
When comparing uncharacterized proteins, researchers should consider:

• Sequence similarity across different yeast species

• Conservation across evolutionary boundaries

• Co-expression patterns under similar conditions

• Shared genetic or protein-protein interactions

• Similar phenotypic effects when deleted or overexpressed

What is the optimal experimental design to determine the physiological function of YHR145C?

An optimal experimental design employs multiple complementary approaches:

• Genetic Manipulation Strategy:

  • Generate precise knockout using CRISPR-Cas9

  • Create overexpression strains with inducible promoters

  • Develop GFP/epitope-tagged versions for localization studies

• Phenotypic Characterization:

  • Growth assays under various stress conditions (oxidative, temperature, pH)

  • Systematic metabolic profiling

  • Cell cycle analysis

  • Microscopic examination for morphological changes

• Molecular Interaction Analysis:

  • Synthetic genetic array analysis to identify genetic interactions

  • Affinity purification coupled with mass spectrometry

  • Yeast two-hybrid screening against the entire proteome

• Multi-omics Integration:

  • Transcriptomic changes in knockout strains

  • Proteomic analysis to identify affected pathways

  • Metabolomic profiling to detect biochemical alterations
    Many uncharacterized genes may be approachable by conventional one-gene-at-a-time hypothesis-driven approaches or by assays that probe specific pathways . For example, if YHR145C contains domains similar to known protein kinases or RNA-binding proteins, targeted biochemical assays could be designed based on these predictions.

How can researchers overcome challenges in studying protein-protein interactions of YHR145C?

Protein-protein interaction studies face several challenges with uncharacterized proteins:

What multi-omics approaches would be most effective for characterizing YHR145C's functional role?

A comprehensive multi-omics approach provides systems-level insights:

• Transcriptomics:

  • RNA-seq comparing wild-type and YHR145C knockout strains

  • Analysis across different growth phases and stress conditions

  • Identification of co-regulated gene clusters

• Proteomics:

  • Quantitative proteome analysis of knockout effects

  • Phosphoproteomics to detect signaling changes

  • Protein-protein interaction network mapping

• Metabolomics:

  • Targeted and untargeted metabolic profiling

  • Flux analysis using isotope-labeled precursors

  • Integration with biochemical pathway maps

• Integrative Analysis:

  • Network construction combining all datasets

  • Pathway enrichment analysis

  • Comparative analysis with known protein functions
    Recent advances in multi-omics characterization have successfully annotated numerous previously uncharacterized proteins. For example, an in silico characterization pipeline that includes subcellular localization, physicochemical properties analysis, and function prediction tools has proven effective for bacterial proteins . A similar approach could be adapted for YHR145C.

How can computational approaches help predict the function of YHR145C?

Computational approaches offer powerful initial insights:

What phenotypes might be associated with YHR145C deletion or overexpression?

Phenotypic analysis provides functional clues:

• Growth Phenotypes:

  • Monitor growth rates under standard conditions

  • Test sensitivity to various stressors (oxidative, temperature, nutrient limitation)

  • Examine tolerance to chemicals and antibiotics

• Cellular Processes:

  • Assess cell cycle progression and cell morphology

  • Examine DNA damage response

  • Monitor protein synthesis and turnover rates

• Specialized Assays:

  • If computational predictions suggest specific functions (e.g., kinase activity), design targeted biochemical assays

  • Test substrate utilization patterns

  • Examine interactions with known cellular pathways
    Some uncharacterized ORFs show significant phenotypes when mutated. For example, YDR185C encodes a "Mitochondrial protein of unknown function" that has similarity to Ups1p, which regulates alternative topogenesis of Mgm1p . YKL098W encodes a 357 amino acid "Putative protein of unknown function" that interacts genetically with both CDC8 and SKP1, involved in DNA synthesis and mitosis, respectively .

How can researchers distinguish between direct and indirect effects when characterizing YHR145C function?

Distinguishing direct from indirect effects requires rigorous experimental controls:

• Complementation Studies:

  • Reintroduce wild-type YHR145C to rescue knockout phenotypes

  • Create point mutations to disrupt specific domains

  • Express orthologous genes from related species

• Temporal Analysis:

  • Use inducible systems to monitor immediate vs. delayed effects

  • Perform time-course experiments after gene induction/repression

  • Monitor primary transcriptional responses

• Biochemical Validation:

  • Perform in vitro assays with purified components

  • Demonstrate direct physical interactions

  • Conduct structure-function relationship studies

• Genetic Interaction Analysis:

  • Construct double mutants with related genes

  • Perform epistasis analysis

  • Use synthetic genetic array techniques to map genetic networks

What are the optimal conditions for expressing and purifying recombinant YHR145C?

Optimizing expression and purification requires systematic testing:

• Expression System Selection:

  • S. cerevisiae: Provides native post-translational modifications

  • E. coli: Higher yields but may lack proper folding

  • Insect cells: Intermediate option for complex proteins

• Expression Optimization:

  • Test different promoters (constitutive vs. inducible)

  • Optimize codon usage for the expression system

  • Determine optimal induction conditions (temperature, time, inducer concentration)

• Protein Solubility Enhancement:

  • Use solubility tags (MBP, SUMO, GST)

  • Test various buffer compositions during lysis

  • Consider co-expression with chaperones

• Purification Strategy:

  • Implement multi-step purification (affinity, ion exchange, size exclusion)

  • Optimize buffer conditions for protein stability

  • Verify purity by SDS-PAGE and mass spectrometry
    For yeast proteins, expression in the native organism often provides advantages for proper folding and post-translational modifications. When expressing recombinant proteins in yeast, the transcription level can be controlled by constitutive promoters like GAPDH, as demonstrated in other recombinant yeast studies .

How can CRISPR-Cas9 technology be optimized for functional studies of YHR145C?

CRISPR-Cas9 offers precise genome editing capabilities:

• Guide RNA Design:

  • Design multiple gRNAs targeting different regions

  • Assess off-target effects computationally

  • Test efficiency in preliminary experiments

• Editing Strategies:

  • Complete knockout via NHEJ repair

  • Precise mutations via HDR with donor templates

  • Endogenous tagging for localization studies

  • CRISPRi for inducible repression without gene deletion

• Validation Approaches:

  • Sequence verification of edited regions

  • Confirmation of protein absence/modification

  • Phenotypic comparison with traditional knockout methods

• Multiplexed Applications:

  • Simultaneous editing of YHR145C and potential interaction partners

  • Creation of combinatorial mutations to test genetic interactions

What advanced structural biology techniques should be prioritized to elucidate YHR145C structure?

Structural characterization requires a multi-technique approach:

How does understanding YHR145C contribute to our knowledge of uncharacterized proteins in yeast?

YHR145C represents one of the many uncharacterized yeast proteins that constitute a significant knowledge gap in yeast biology. As of 2007, there were still over 1000 uncharacterized genes in yeast, representing approximately 15% of the genome . Successfully characterizing YHR145C would:

• Methodological Advancement:

  • Validate approaches for characterizing other uncharacterized proteins

  • Establish a pipeline for systematic functional annotation

  • Demonstrate the value of integrated multi-omics approaches

• Biological Understanding:

  • Potentially reveal novel cellular pathways or mechanisms

  • Clarify evolutionary relationships between conserved uncharacterized proteins

  • Help complete our understanding of the yeast genetic landscape

• Broader Implications:

  • Provide insights applicable to orthologous proteins in other organisms

  • Contribute to understanding fundamental eukaryotic cellular processes

  • Support systems biology modeling of yeast metabolism and regulation
    The comprehensive characterization of uncharacterized proteins advances our understanding of cellular functions and might reveal novel biological mechanisms that have been overlooked in previous studies.

What are the most promising research directions for understanding the biological significance of YHR145C?

Future research should focus on several complementary approaches:

• Condition-Specific Functions:

  • Test YHR145C function under various stress conditions

  • Examine its role during different growth phases

  • Investigate possible involvement in specialized cellular processes

• Evolutionary Context:

  • Compare function across different yeast species

  • Identify selective pressures through population genomics

  • Trace evolutionary history of domain architecture

• Regulatory Networks:

  • Map transcriptional regulation of YHR145C

  • Identify post-translational modifications

  • Characterize dynamic changes in interaction networks

• Translational Applications:

  • Explore biotechnological applications if specific functions are discovered

  • Investigate potential as a drug target if disease-relevant
    Studies of previously uncharacterized proteins have led to significant discoveries. For example, RTT109, although previously known to influence Ty transposition, was later described as encoding a histone H3-K56 acetyltransferase by at least five different research groups .

How can contradictory experimental results about YHR145C be reconciled and interpreted?

Resolving experimental contradictions requires systematic analysis:

• Experimental Conditions Analysis:

  • Compare exact experimental conditions (media, temperature, strain background)

  • Examine differences in genetic constructs used

  • Consider variations in measurement techniques and sensitivities

• Strain-Specific Effects:

  • Test in multiple strain backgrounds

  • Consider genetic interactions specific to laboratory strains

  • Sequence verify the YHR145C locus in all strains used

• Multifaceted Functions:

  • Consider that YHR145C may have multiple distinct functions

  • Investigate condition-specific activities

  • Examine protein interaction networks under different conditions

• Systematic Validation:

  • Design experiments that directly test conflicting hypotheses

  • Implement orthogonal techniques to verify results

  • Perform collaborative cross-laboratory validation studies Understanding that proteins often have context-dependent functions helps reconcile apparent contradictions in experimental results. This is particularly relevant for uncharacterized proteins where our knowledge framework is still developing.