Recombinant Saccharomyces cerevisiae Putative uncharacterized membrane protein YJL175W (YJL175W)

What is the genomic context of YJL175W in S. cerevisiae?

YJL175W is located on chromosome X of the Saccharomyces cerevisiae genome. The gene encodes a putative membrane protein with no clearly characterized function to date. Based on genomic organization studies similar to those used in Ty element research, the genomic context can be analyzed through:

• Identification of adjacent genes and their orientations

• Analysis of potential regulatory elements in the promoter region

• Investigation of conservation across Saccharomyces species

Methodological approach: Use the Saccharomyces Genome Database (SGD) to identify chromosomal coordinates and flanking genes. Perform comparative genomic analysis with other yeast species using BLAST and multiple sequence alignment tools. Analyze promoter regions for transcription factor binding sites using motif discovery algorithms .

What are the predicted structural characteristics of YJL175W?

Bioinformatic analysis suggests YJL175W contains multiple transmembrane domains characteristic of integral membrane proteins. Structural predictions indicate:

Methodological approach: Generate a construct expressing YJL175W with a C-terminal fluorescent tag. Transform S. cerevisiae using the lithium acetate method described by Ito et al. . Visualize cellular localization using confocal microscopy and confirm membrane association through subcellular fractionation followed by Western blot analysis.

How can I effectively express and purify recombinant YJL175W for biochemical studies?

As a membrane protein, YJL175W presents specific challenges for recombinant expression and purification:

• Expression system selection:

  • Homologous expression in S. cerevisiae under GAL1 promoter

  • Heterologous expression in Pichia pastoris for higher yield

  • E. coli strains specialized for membrane proteins (C41/C43)

• Purification strategy:

  • Membrane isolation by differential centrifugation

  • Solubilization screening with different detergents

  • Affinity chromatography using epitope tags

  • Size exclusion chromatography for final purity

Methodological approach: Clone YJL175W with an N- or C-terminal affinity tag (His6, FLAG, etc.) into an appropriate expression vector. For yeast expression, transform using the lithium acetate method . Optimize expression conditions (temperature, induction time, media composition). For membrane isolation, disrupt cells mechanically and separate membranes by ultracentrifugation. Test multiple detergents (DDM, LMNG, GDN) for optimal solubilization while maintaining protein stability.

What methods are available to study YJL175W gene expression regulation?

To investigate the regulation of YJL175W expression:

• Transcriptional analysis:

  • RT-qPCR for targeted expression analysis

  • Northern blotting for transcript size verification

  • RNA-Seq for genome-wide expression context

• Promoter analysis:

  • Reporter gene assays with truncated promoter constructs

  • Chromatin immunoprecipitation (ChIP) to identify bound transcription factors

  • CRISPR interference for targeted repression

Methodological approach: Generate a series of promoter-reporter constructs with varying lengths of the YJL175W upstream region fused to a reporter gene (GFP, lacZ). Transform these constructs into wild-type yeast and relevant transcription factor mutants. Measure reporter activity under different growth conditions and stress treatments to identify regulatory elements and factors .

How might YJL175W interact with DNA recombination and repair pathways in S. cerevisiae?

Given the complex interplay between cellular systems in yeast, YJL175W may have functional connections to DNA maintenance pathways:

• Generate double mutants of YJL175W with key recombination genes:

  • Δyjl175w Δrad50

  • Δyjl175w Δrad51

  • Δyjl175w Δrad52

  • Δyjl175w Δrad54

  • Δyjl175w Δrad57

• Assess phenotypes related to DNA damage and repair:

  • Sensitivity to DNA-damaging agents (UV, MMS, γ-radiation)

  • Recombination rates using appropriate reporter systems

  • Chromosomal stability and mutation frequency

Methodological approach: Create deletion strains using PCR-based gene replacement techniques. Assess DNA damage sensitivity through spot assays with serial dilutions on plates containing varying concentrations of DNA-damaging agents. Measure recombination rates using systems similar to those employed in Ty1 transposition studies . Genetic interactions can be evaluated through epistasis analysis comparing single and double mutants.

What role does YJL175W play in cellular stress responses?

As a membrane protein, YJL175W may contribute to maintaining cellular homeostasis under stress conditions:

Methodological approach: Compare growth of wild-type and ΔyjL175W strains under various stress conditions using both plate-based assays and liquid culture growth curves. Monitor membrane integrity using fluorescent dyes like propidium iodide. Analyze the transcriptional response to stress using RNA-Seq or microarray analysis to identify genes co-regulated with YJL175W during stress adaptation .

How does YJL175W interact with other membrane proteins and cellular components?

Understanding the protein interaction network of YJL175W provides insights into its function:

Methodological approach: Express epitope-tagged YJL175W in yeast and perform affinity purification coupled with mass spectrometry (AP-MS). For membrane proteins, optimize membrane solubilization conditions with various detergents. Validate identified interactions using reciprocal co-immunoprecipitation, bimolecular fluorescence complementation (BiFC), or split-ubiquitin yeast two-hybrid systems specifically designed for membrane proteins .

How does the functional characterization of YJL175W inform our understanding of uncharacterized membrane proteins in other organisms?

Comparative genomics approaches reveal:

• Identification of YJL175W homologs in related species:

  • Sequence similarity searches against fungal genomes

  • Structural conservation analysis

  • Synteny examination

• Functional conservation testing:

  • Complementation experiments with homologs

  • Phenotypic analysis of corresponding mutants

  • Localization comparison across species

Methodological approach: Identify potential homologs using BLAST searches against sequenced fungal genomes. Align sequences to determine conservation patterns and construct phylogenetic trees to visualize evolutionary relationships. Test functional conservation by expressing homologs in ΔyjL175W yeast strains and assessing phenotypic rescue. This approach parallels methods used in RAD gene family characterization across species .

What is the optimal protocol for generating YJL175W mutants for functional studies?

For comprehensive functional analysis:

• Complete deletion strain construction:

  • PCR-amplify a selectable marker (KanMX) with primers containing 40-50bp homology to regions flanking YJL175W

  • Transform PCR product into S. cerevisiae

  • Select transformants on appropriate media

  • Confirm deletion by PCR and phenotypic analysis

• Site-directed mutagenesis for specific residue analysis:

  • Identify conserved or predicted functional residues

  • Design mutagenic primers for PCR-based site-directed mutagenesis

  • Transform mutant constructs into ΔyjL175W strain

  • Assess functional consequences of specific mutations

Methodological approach: Use the lithium acetate transformation method described by Ito et al. . For targeted mutagenesis, consider conserved residues identified through multiple sequence alignments. Create a panel of mutations affecting different protein regions (transmembrane domains, loops, termini) to dissect domain-specific functions.

How can I study YJL175W localization and dynamics in living cells?

To visualize YJL175W behavior in vivo:

• Fluorescent protein tagging strategies:

  • C-terminal GFP fusion for minimal functional disruption

  • Split-GFP approaches for topology determination

  • Photoactivatable fluorescent proteins for dynamic studies

• Advanced microscopy techniques:

  • Confocal microscopy for co-localization studies

  • FRAP (Fluorescence Recovery After Photobleaching) for mobility analysis

  • Single-molecule tracking for detailed dynamic behavior

Methodological approach: Generate a C-terminal fusion of YJL175W with GFP or mCherry using PCR-based tagging methods. Express the construct under the native promoter to maintain physiological expression levels. Perform colocalization studies with markers for different cellular compartments (ER, Golgi, plasma membrane, vacuole). For dynamic studies, use FRAP to measure protein mobility within membranes under different conditions .

What are the recommended approaches for studying YJL175W's role in stress response pathways?

To characterize stress-related functions:

• Comprehensive stress phenotyping:

  • Growth assays under various stressors

  • Viability measurements following acute stress

  • Morphological examination during stress adaptation

• Molecular response characterization:

  • Transcriptional profiling during stress response

  • Protein abundance and modification changes

  • Genetic interaction mapping under stress conditions

Methodological approach: Expose wild-type and ΔyjL175W strains to a panel of stressors at varying intensities and durations. Monitor growth using plate-based assays and automated growth curve analysis. For molecular responses, collect cells at different time points after stress exposure and analyze transcriptional changes using RNA-Seq or RT-qPCR for specific target genes. Examine protein level changes and post-translational modifications using Western blotting .

How can I determine if YJL175W forms complexes with other proteins in the membrane?

To characterize protein complexes:

• In vivo complex identification:

  • Blue native PAGE for native complex isolation

  • Co-immunoprecipitation with crosslinking

  • Proximity labeling approaches (BioID, APEX)

• Complex characterization:

  • Mass spectrometry for composition analysis

  • Size exclusion chromatography for complex size determination

  • Functional reconstitution of purified complexes

Methodological approach: Solubilize membranes under mild conditions to preserve protein-protein interactions. Separate complexes using blue native PAGE or size exclusion chromatography. For specific interactions, use co-immunoprecipitation with tagged YJL175W followed by Western blotting for suspected interaction partners. For unbiased discovery, couple affinity purification with mass spectrometry, similar to approaches used in characterizing DNA repair protein complexes .

How should RNA-Seq data be analyzed to identify genes co-regulated with YJL175W?

The differential gene expression profile in YJL175W deletion strains reveals functional connections:

Methodological approach: Perform RNA-Seq on wild-type and ΔyjL175W strains under standard conditions and various stresses. Process raw sequencing data through quality control, alignment to the reference genome, and quantification of transcript abundance. Identify differentially expressed genes using statistical packages like DESeq2 or edgeR. Perform Gene Ontology enrichment analysis to identify biological processes affected by YJL175W deletion .

What bioinformatic approaches can predict functional domains and critical residues in YJL175W?

Computational analysis reveals structural features informing experimental design:

• Sequence-based predictions:

  • Conservation analysis across fungal species

  • Identification of known protein domains

  • Prediction of functional motifs (phosphorylation sites, etc.)

• Structure-based predictions:

  • Transmembrane topology modeling

  • Homology modeling if structural homologs exist

  • Molecular dynamics simulations for functional insights

Methodological approach: Perform multiple sequence alignment of YJL175W with homologs from related species. Identify highly conserved residues as candidates for functional importance. Use specialized membrane protein structure prediction tools like MEMSAT and TOPCONS to predict transmembrane regions and topology. Apply these approaches similar to those used in characterizing other yeast membrane proteins .

How does YJL175W potentially interact with DNA repair and recombination pathways?

The relationship between membrane proteins and DNA maintenance:

• Genetic interaction analysis:

  • Growth phenotypes of double mutants with RAD genes

  • Synthetic genetic array (SGA) screening

  • Targeted epistasis studies with key pathway components

• DNA damage and recombination phenotypes:

  • Mutation rates in YJL175W deletion strains

  • Recombination frequency measurements

  • DNA damage checkpoint activation analysis

Methodological approach: Create double mutants of YJL175W with genes involved in the RAD52 recombinational repair pathway (RAD50, RAD51, RAD52, RAD54, RAD57). Assess these strains for sensitivity to DNA damaging agents and changes in recombination rates. Use reporter systems similar to those employed in Ty1 transposition studies to measure recombination frequency .

What approaches can distinguish direct versus indirect effects in YJL175W phenotypic studies?

To establish causality in observed phenotypes:

• Complementation strategies:

  • Expression of wild-type YJL175W in deletion strain

  • Structure-function analysis with mutant variants

  • Temporal control using inducible promoters

• Acute inactivation approaches:

  • Auxin-inducible degron tagging for rapid protein depletion

  • Temperature-sensitive alleles for conditional function

  • Chemical-genetic approaches for specific inhibition

Methodological approach: Generate a series of YJL175W variants with different mutations and test their ability to complement the phenotypes of a ΔyjL175W strain. For temporal control, place YJL175W under an inducible promoter like GAL1 or use degron tagging for controlled protein depletion. These approaches allow differentiation between primary (direct) effects of YJL175W loss and secondary (indirect) consequences .

How might YJL175W research inform our understanding of membrane protein evolution?

Evolutionary analysis provides context for functional studies:

• Phylogenetic distribution:

  • Presence/absence patterns across fungal species

  • Sequence divergence rates compared to other membrane proteins

  • Identification of selective pressures

• Structural evolution:

  • Conservation of transmembrane domains versus loop regions

  • Evolution of post-translational modification sites

  • Correlation with cellular complexity across species

Methodological approach: Perform comprehensive phylogenetic analysis of YJL175W across fungal species. Calculate selection metrics (dN/dS ratios) to identify regions under purifying or positive selection. Compare evolutionary patterns with those of characterized membrane proteins to place YJL175W in evolutionary context .

What potential biotechnological applications might arise from YJL175W characterization?

Applied research directions:

• Stress tolerance engineering:

  • Modification of YJL175W expression for improved industrial strain robustness

  • Development of stress biosensors based on YJL175W regulation

  • Novel antifungal targets based on mechanism insights

• Membrane protein production platform:

  • Optimization of expression systems for difficult membrane proteins

  • Development of new solubilization and stabilization strategies

  • Advancement of structural biology approaches for membrane proteins

Methodological approach: Test whether overexpression or modified versions of YJL175W can enhance yeast tolerance to industrial stresses. Develop biosensors by fusing the YJL175W promoter to reporter genes if it shows specific stress responsiveness. Apply knowledge gained from YJL175W structural studies to improve expression and purification of other challenging membrane proteins .