YLR419W Antibody

What is YLR419W and what is its functional significance in yeast?

YLR419W encodes a protein of 1435 amino acids with a molecular weight of 163 kDa in Saccharomyces cerevisiae. Recent research has definitively identified it as the yeast homolog of the mammalian translation initiation factor DHX29. The protein contains multiple functional domains that contribute to its role in translation .

Key structural domains of YLR419W protein include:

These domains are characteristic of the superfamily 2 DEAH/DExH-box helicases, which participate in ATP-dependent unwinding of RNA duplexes .

How does YLR419W interact with the ribosome?

YLR419W protein physically associates with the ribosome, primarily with the 40S subunit. Sucrose gradient experiments with polysome extracts show that YLR419W-TAP fusion protein sediments mainly in the 80S peak, but also appears in polysome fractions and the 40S fraction. This sedimentation profile persists even after RNase treatment, suggesting a direct association with the ribosome rather than an RNA-mediated interaction .

Cross-linking and analysis of cDNA (CRAC) experiments have precisely identified that YLR419W contacts the 18S ribosomal RNA at positions 467-519, with the crosslink point specifically at positions 492-494. This region corresponds to the H16 helix located outside the protein-rRNA condensate block of the ribosome .

What applications is the YLR419W antibody suitable for?

The YLR419W antibody has been validated for several research applications:

• ELISA (Enzyme-Linked Immunosorbent Assay)

• Western Blotting (WB)

• Identification of the YLR419W antigen in Saccharomyces cerevisiae

When designing experiments, researchers should note that the antibody is specifically reactive against Saccharomyces cerevisiae (strain ATCC 204508/S288c) and has been antigen-affinity purified to ensure specificity .

What are the optimal storage and handling conditions for YLR419W antibody?

For YLR419W antibody preservation and functionality:

• Store the antibody at -20°C or -80°C immediately upon receipt

• Avoid repeated freeze-thaw cycles, which can compromise antibody integrity

• The antibody is supplied in liquid form with a buffer composed of:

  • 0.03% Proclin 300 (preservative)

  • 50% Glycerol

  • 0.01M PBS at pH 7.4

When designing long-term studies, prepare aliquots of the antibody before freezing to minimize freeze-thaw cycles.

How should Western blot conditions be optimized for YLR419W detection?

When performing Western blot analysis with YLR419W antibody:

• Separate proteins on polyacrylamide gel (4-12% Bis-Tris gradient gels have been successfully used)

• Transfer proteins to nitrocellulose membrane

• For detection of YLR419W-TAP fusion protein, PAP (Peroxidase Anti-Peroxidase) at 1/5,000 dilution has been effective

• Visualization can be achieved with clarity ECL substrate

• As YLR419W is a high molecular weight protein (163 kDa), extend transfer time and use appropriate molecular weight markers

For polysome profile analysis experiments, researchers should note that YLR419W-TAP can be detected in 40S, 80S, and polysome fractions, with appropriate controls such as Rpl1 detection .

What methodological approaches can be used to study YLR419W's ribosomal interactions?

To investigate YLR419W's interactions with the ribosome, consider these methodologies that have yielded significant results:

• Sucrose gradient analysis with polysome extracts:

  • Cultivate yeast strains in rich medium until OD600 reaches appropriate density

  • Treat cells with cycloheximide to stabilize polysomes

  • Prepare cellular extracts and load on sucrose gradients

  • After centrifugation, collect fractions and analyze protein distribution by Western blotting

• Cross-linking and analysis of cDNA (CRAC) experiments:

  • Generate strains expressing YLR419W-HTP (His6-TEV-Protein A) fusion

  • Perform UV crosslinking to covalently attach RNA to the protein

  • Immunoprecipitate the protein-RNA complexes

  • Moderately digest bound RNAs

  • Identify interaction sites through deep sequencing

• RNase treatment controls:

  • Treat cellular extracts with RNase prior to sucrose gradient analysis

  • This helps distinguish direct ribosome binding from RNA-mediated interactions

How does YLR419W's function compare with its mammalian homologs?

YLR419W has been identified as having three potential mammalian homologs: DHX29, DHX36, and DHX57. Through functional studies, DHX29 has been confirmed as the closest functional homolog. The comparative properties of these proteins include:

Both structural analysis and functional studies indicate that YLR419W and DHX29 bind to the same region of the ribosomal 40S subunit, specifically the H16 helix of the 18S rRNA .

What is the impact of YLR419W deficiency on cellular functions?

Studies involving YLR419W homologs in other fungi provide insights into the potential impacts of YLR419W deficiency:

In Neurospora crassa, deficiency of MSP-8 (the YLR419W homolog) leads to:

• Suppressed protein translation

• Multidrug resistance to various antifungal agents

• Reduced reactive oxygen species (ROS) levels

• Decreased expression of oxidative stress-related proteins

• Resistance to translation elongation inhibitors like cycloheximide

This suggests YLR419W may play crucial roles beyond translation initiation, potentially affecting cellular stress responses and drug sensitivity. When designing YLR419W knockout or depletion studies, researchers should monitor these parameters to fully characterize phenotypic effects.

How can structured 5'UTR reporter systems be designed to assess YLR419W function?

To evaluate YLR419W's role in unwinding structured 5'UTRs during translation:

• Reporter system design:

  • Construct reporter plasmids containing a standard reporter gene (e.g., luciferase or GFP)

  • Engineer 5'UTRs with varying degrees of secondary structure

  • Include positive controls (unstructured 5'UTRs) and negative controls (highly structured 5'UTRs)

• Experimental approach:

  • Transform constructs into wild-type and YLR419W-deficient yeast strains

  • Measure reporter protein expression levels using appropriate assays

  • Analyze translation efficiency by comparing protein levels to mRNA levels

  • Consider polysome profiling to assess ribosome loading on structured mRNAs

• Data analysis considerations:

  • Normalize reporter expression to account for differences in mRNA levels

  • Compare translation efficiency between wild-type and YLR419W-deficient strains

  • Correlate translation efficiency with predicted 5'UTR structure stability

What are the critical parameters for validating a YLR419W antibody?

When validating a newly produced or purchased YLR419W antibody:

• Specificity validation:

  • Western blot analysis using wild-type and YLR419W knockout yeast strains

  • Immunoprecipitation followed by mass spectrometry to confirm target identity

  • Preabsorption with recombinant YLR419W protein to confirm specific binding

• Application-specific validation:

  • For ELISA: Determine optimal coating concentrations, antibody dilutions, and detection methods

  • For Western blot: Optimize sample preparation, transfer conditions, and antibody concentrations

  • For immunoprecipitation: Establish appropriate binding and washing conditions

• Cross-reactivity assessment:

  • Test reactivity against homologous proteins in other yeasts if working with multiple species

  • Determine if the antibody recognizes specific domains or epitopes of YLR419W

How can CRAC experiments with YLR419W be optimized to identify RNA interaction sites?

To optimize CRAC (Cross-linking and Analysis of cDNA) experiments for YLR419W RNA interaction studies:

• Strain preparation:

  • Use YLR419W-HTP (His6-TEV-Protein A) tagged strains

  • Consider including spike-in controls from related species (e.g., S. pombe cells with tagged homologs)

• Crosslinking optimization:

  • Perform UV crosslinking in vivo

  • Include non-crosslinked controls to identify background binding

• Purification and library preparation:

  • Perform protein purification steps directly on sepharose beads

  • Use GelFree separation to collect appropriate molecular weight fractions

  • Include appropriate 5' ligation primers for sample identification

• Data analysis:

  • Look for specific deletions/mutations at contact sites which represent crosslink points

  • Map interaction sites to ribosomal RNA or other RNA structures

  • Compare with known binding sites of homologous proteins in other species

What are the key considerations when designing TAP-tag vs. HTP-tag YLR419W fusion proteins for different experimental applications?

Different protein tags offer advantages for specific experimental applications:

When selecting between these tags:

• Consider the experimental goal (protein complex vs. RNA interaction studies)

• Evaluate potential functional interference due to tag size and position

• Test the tagged protein for complementation of knockout phenotypes

• Validate appropriate expression levels of the fusion protein

How does the function of YLR419W relate to multidrug resistance mechanisms in fungi?

Recent research with the N. crassa homolog of YLR419W (MSP-8) has revealed a surprising connection between this protein family and drug resistance:

• Observed phenotypes in MSP-8 deficient strains:

  • Increased resistance to multiple antifungal drugs including azoles, amphotericin B, and polyoxin B

  • Reduced intracellular drug accumulation

  • Decreased reactive oxygen species (ROS) levels

  • Downregulation of oxidative stress-related proteins

• Mechanistic insights:

  • MSP-8/YLR419W deficiency appears to suppress protein translation

  • This translation suppression may alter the expression of proteins involved in drug transport and metabolism

  • Reduced ROS levels create a physiological environment that contributes to drug tolerance

  • The deletion of related proteins (e.g., CEM-5) similarly enhances multidrug resistance

These findings suggest that YLR419W's role in translation may indirectly impact drug sensitivity through global changes in protein expression patterns.

What computational approaches can predict the impact of YLR419W mutations on ribosome binding?

To predict how mutations in YLR419W might affect ribosome binding:

• Structural modeling approaches:

  • Use the identified binding site in 18S rRNA (H16 helix) as a constraint

  • Generate homology models based on the structure of mammalian DHX29

  • Perform molecular docking with the ribosomal binding site

  • Simulate the effects of mutations on binding energy and interface contacts

• Sequence conservation analysis:

  • Compare YLR419W sequences across different yeast species

  • Identify highly conserved residues, particularly in regions corresponding to helicase domains

  • Prioritize conserved residues at domain interfaces for mutational analysis

• Functional domain integrity assessment:

  • Predict how mutations might disrupt the helicase ATP-binding, UBA, or HA2 domains

  • Evaluate potential changes in protein stability using tools like FoldX

  • Consider effects on ATP binding and hydrolysis for mutations in the DEAD-like domain

How can the evolutionary relationship between YLR419W and its homologs inform functional studies?

Evolutionary analysis of YLR419W and its homologs provides important context for experimental design:

• Phylogenetic considerations:

  • Despite the evolutionary distance between humans and yeast, key functional domains in DEAH/DExH-box helicases are conserved

  • DHX29, DHX36, and DHX57 represent distinct evolutionary paths from a common ancestor with YLR419W

  • The conservation of ribosome binding sites suggests strong selective pressure on this function

• Functional divergence analysis:

  • DHX29 maintains the translation initiation function seen in YLR419W

  • DHX36 has evolved additional capabilities to bind G-quadruplex structures

  • The function of DHX57 remains largely unknown but may represent further functional diversification

  • These patterns suggest that YLR419W represents an ancestral function that has been conserved in DHX29 but modified in other lineages

• Cross-species complementation studies:

  • Experimental replacement of YLR419W with human DHX29 could test functional conservation

  • Examining whether YLR419W can complement DHX29 deficiency in mammalian cells would provide insight into conserved functions

  • Domain swapping experiments between YLR419W and its homologs could identify regions responsible for specialized functions

This evolutionary perspective helps researchers design experiments that leverage the conservation and divergence patterns to better understand YLR419W's fundamental functions and specializations.