YCR016W Antibody

What is YCR016W/Rbp95 and what is its function in ribosome biogenesis?

YCR016W, also known as Rbp95, is a novel ribosome assembly factor that functions as a constituent of early pre-60S ribosomal particles. It plays a critical role in ribosome synthesis by binding to helix H95 in the 3′ region of the 25S rRNA and cooperating with the Npa1 complex during pre-60S particle maturation . The protein contains two independent RNA-interacting domains that enable it to bind to both 25S rRNA and several small nucleolar RNAs (snoRNAs) . Functionally, Rbp95 appears to promote pre-rRNA folding events within pre-60S particles, as its absence results in alterations in the protein composition of early pre-60S particles and delays their maturation .

How does Rbp95 interact with other components of the ribosome assembly machinery?

Rbp95 has been shown to be both genetically and physically linked to most Npa1 complex members and to ribosomal protein Rpl3 . Synthetic lethal screening has identified genetic interactions between Rbp95 and several key ribosomal assembly factors including NPA1, NPA2, RPL3, RSA3, DBP6, and DBP9 . The table below summarizes some key interactions:

These interactions suggest that Rbp95 functions cooperatively with the Npa1 complex during the early stages of pre-60S maturation, potentially through coordinated binding to specific rRNA regions .

What are the validated applications for YCR016W antibody in ribosome biogenesis research?

The YCR016W (Rbp95) antibody has been validated for multiple applications in ribosome biogenesis research:

These applications make the antibody a valuable tool for studying Rbp95's role in ribosome assembly and its interactions with other components of the ribosomal machinery.

What is the recommended protocol for detecting Rbp95-RNA interactions using YCR016W antibody?

To detect Rbp95-RNA interactions, researchers can employ UV crosslinking followed by RNA extraction and RT-PCR . The protocol typically involves:

• UV crosslinking of cells expressing Rbp95-HTP (His6-TEV-ProtA) to stabilize protein-RNA interactions

• Immunoprecipitation of Rbp95-HTP using the YCR016W antibody

• Extraction of Rbp95-bound RNA from the immunoprecipitated complex

• Reverse transcription using SuperScript III reverse transcriptase and specific primers (e.g., miRcatRT: 5′-CCT TGG CAC CCG AGA ATT-3′)

• PCR amplification of the cDNA using appropriate primers (e.g., P5F and P3R primers)

• Analysis of the resulting PCR products to identify Rbp95-bound RNAs

Control samples should include wild-type strains (BY4742) processed in parallel to identify specific Rbp95-RNA interactions . This methodology has successfully demonstrated that Rbp95 associates with helix H95 in the 3′ region of 25S rRNA and with several snoRNAs .

How can researchers investigate the functional relationship between Rbp95 and the Npa1 complex using the YCR016W antibody?

Investigating the functional relationship between Rbp95 and the Npa1 complex requires a multi-faceted approach:

• Co-immunoprecipitation studies: Use the YCR016W antibody to pull down Rbp95 and analyze co-precipitating Npa1 complex components (Npa1, Npa2, Rsa3, Dbp6) by Western blotting using specific antibodies .

• Synthetic genetic analysis: Combine Rbp95 mutations with mutations in Npa1 complex members and assess growth phenotypes. Previous studies have shown that combined mutation of Rbp95 and Npa1 complex members leads to delays in the maturation of early pre-60S particles .

• RNA-binding competition/cooperation assays: Analyze how the presence of Npa1 complex components affects Rbp95 binding to rRNA targets using the YCR016W antibody in RNA immunoprecipitation experiments.

• Structural studies: Use the YCR016W antibody to isolate Rbp95-containing complexes for structural analysis by cryo-EM to determine spatial relationships with Npa1 complex components.

These approaches can provide insights into whether Rbp95 and the Npa1 complex act sequentially, cooperatively, or antagonistically during pre-60S maturation .

What methods can distinguish between the two RNA-binding domains of Rbp95, and how does this inform our understanding of its function?

To distinguish between the two independent RNA-interacting domains of Rbp95:

• Domain-specific antibody generation: Develop antibodies that specifically recognize each RNA-binding domain to investigate their individual contributions to RNA binding.

• Mutational analysis: Generate Rbp95 variants with mutations in each domain separately, then use the YCR016W antibody in RNA immunoprecipitation assays to determine how each domain contributes to binding different RNA targets.

• Structural characterization: Perform structural studies on individual domains and their complexes with RNA to understand the mechanistic basis of their interactions.

• Domain-swapping experiments: Replace one RNA-binding domain with an unrelated domain and assess functional consequences.

Understanding the distinct roles of these domains provides insight into how Rbp95 may coordinate the binding of different RNA species (25S rRNA and snoRNAs) and potentially promote structural rearrangements during pre-60S particle maturation .

What controls should be included when using YCR016W antibody in RNA immunoprecipitation experiments?

When conducting RNA immunoprecipitation (RIP) experiments with YCR016W antibody, several critical controls should be included:

• Knockout/depletion control: Include samples from Δrbp95 strains to confirm antibody specificity .

• Non-specific antibody control: Use an isotype-matched irrelevant antibody to assess background binding.

• RNA integrity control: Analyze input RNA quality and perform RNase treatment controls to confirm RNA-dependent interactions.

• Crosslinking controls: Compare UV-crosslinked samples with non-crosslinked samples to distinguish direct versus indirect RNA interactions.

• Competing RNA controls: Add excess non-specific RNA to assess binding specificity.

• Sequential immunoprecipitation: For co-factor studies, perform sequential IP with antibodies against Rbp95 and potential interacting partners (e.g., Npa1 complex members).

These controls help distinguish specific Rbp95-RNA interactions from background and provide confidence in the identified RNA targets .

What methodological approaches can resolve discrepancies between in vitro and in vivo RNA binding studies with Rbp95?

To address discrepancies between in vitro and in vivo RNA binding studies of Rbp95:

• Physiological buffer conditions: Adjust in vitro binding conditions to more closely mimic the cellular environment, including appropriate salt concentrations, pH, and molecular crowding agents.

• Co-factor addition: Include known interacting proteins (e.g., Npa1 complex members) in in vitro binding assays to reconstitute functional complexes.

• Structured RNA substrates: Use properly folded RNA substrates that preserve the three-dimensional structure of binding sites rather than linear fragments.

• CLIP-seq approaches: Employ crosslinking and immunoprecipitation followed by high-throughput sequencing to obtain a genome-wide view of RNA binding sites in vivo.

• Comparison with genetic data: Correlate binding data with genetic interaction profiles to identify functionally relevant binding events.

• Single-molecule approaches: Use techniques like FRET to observe binding dynamics that may be missed in bulk assays.

These approaches can help reconcile differences between in vitro and in vivo findings and provide a more complete understanding of Rbp95's RNA binding properties .

How can YCR016W antibody be used to investigate the role of Rbp95 in disease models of ribosomopathies?

The YCR016W antibody can be valuable for investigating connections between Rbp95 function and human ribosomopathies:

• Ortholog identification: Use the antibody to help identify and characterize human orthologs of Rbp95 through immunological cross-reactivity or epitope mapping.

• Functional conservation studies: Examine whether human Rbp95 orthologs can complement yeast Δrbp95 strains, using the antibody to confirm expression.

• Disease-associated mutations: Introduce mutations corresponding to human disease variants into yeast Rbp95 and use the antibody to assess effects on protein stability, localization, and interactions.

• Pre-ribosomal composition analysis: Compare pre-ribosomal particles in wild-type and disease models using the antibody to immunoprecipitate complexes for proteomic analysis.

• Therapeutic target validation: Use the antibody to evaluate Rbp95 as a potential therapeutic target in ribosomopathy models.

These approaches can provide insights into ribosome assembly defects linked to human diseases and potentially identify new therapeutic strategies for ribosomopathies.

What novel methodologies can be combined with YCR016W antibody for studying temporal dynamics of Rbp95 during ribosome assembly?

To study the temporal dynamics of Rbp95 during ribosome assembly:

• Time-resolved immunoprecipitation: Perform Rbp95 immunoprecipitation at different time points after inducing ribosome biogenesis, then analyze associated proteins and RNAs.

• Pulse-chase experiments: Combine metabolic labeling of newly synthesized RNA with Rbp95 immunoprecipitation to track the protein's association with maturing pre-ribosomes.

• Single-particle tracking: Use fluorescently-labeled anti-YCR016W antibody fragments for live-cell imaging of Rbp95 dynamics.

• FRAP analysis: Perform fluorescence recovery after photobleaching on Rbp95-GFP fusions, validated with the antibody, to assess protein exchange rates on pre-ribosomes.

• Proximity labeling: Combine the antibody with techniques like BioID or APEX to capture transient interactions during ribosome assembly.

• Cryo-electron tomography: Use antibody labeling to identify Rbp95 within assembling ribosomes captured at different maturation stages.

These approaches can reveal the dynamic behavior of Rbp95 during ribosome biogenesis and provide insights into the coordination of assembly factor activities .