RR10 Antibody

What is the RR10/ARR10 antibody and what is its target in plant research?

The RR10 antibody is an immunological reagent that targets the Two-component response regulator ARR10 (AT4G31920, O49397) in Arabidopsis and related species . ARR10 functions as a transcription factor in the cytokinin signaling pathway, acting in concert with other type-B ARRs, particularly ARR1 and ARR12 . This antibody allows researchers to detect, quantify, and study the localization and activity of ARR10 protein, which plays critical roles in plant development, growth regulation, and stress responses.

What species cross-reactivity has been validated with RR10/ARR10 antibodies?

The RR10 antibody demonstrates cross-reactivity across multiple plant species, making it valuable for comparative studies:

This cross-reactivity profile enables researchers to investigate ARR10 function across different plant families and comparative evolutionary studies of cytokinin signaling .

What are the optimal storage and handling conditions for maintaining RR10 antibody activity?

For maximum stability and performance in experimental applications, RR10 antibody requires specific handling:

• The antibody is typically provided in lyophilized form

• Use a manual defrost freezer and strictly avoid repeated freeze-thaw cycles

• Upon receipt (typically shipped at 4°C), store immediately at the recommended temperature

• For reconstitution, follow manufacturer's specific guidelines for buffer composition and concentration

• Working dilutions should be prepared fresh before use to maintain optimal binding activity

Improper storage can lead to antibody degradation, resulting in decreased sensitivity and specificity in experimental applications.

What immunostaining protocols are optimal for RR10 antibody in fixed plant tissues?

For successful immunohistochemical detection of ARR10 in plant tissues, the following optimized protocol has been validated:

• Prepare 5 μm FFPE (formalin-fixed paraffin-embedded) sections from plant tissues

• Deparaffinize thoroughly using Histoclear (National Diagnostics)

• Rehydrate through a series of graded methanol steps

• Perform antigen retrieval using [1X] R-Universal buffer (AP0530) in a 2100 antigen retriever for a single heat-pressure cycle

• Permeabilize sections with 0.05% (v/v) Triton X-100-PBS solution for 20 minutes

• Block with Section Block 'ready-to-use' (AP0471) for 30 minutes at room temperature

• Incubate with primary RR10 antibody overnight at 4°C for 16 hours at appropriate dilution (in Antibody Diluent 'FF/PE Sections')

• For phospho-specific detection, add 10 μg/ml of the non-phospho peptide used to raise the antibody per 2 μg/ml antibody

• Include negative controls by omitting primary antibody

• Wash thoroughly (50× dips in 0.05% Triton X-100-PBS, 3 rounds)

• Incubate with pre-absorbed fluorochrome-conjugated secondary antibodies for 1 hour at room temperature

• Mount using Prolong Gold antifade and allow 48-72 hours curing time before sealing

This protocol maximizes signal specificity while minimizing background staining in plant tissue sections.

How can RR10 antibody be effectively utilized in ChIP-seq experiments to study ARR10 transcriptional networks?

Chromatin immunoprecipitation followed by sequencing (ChIP-seq) using RR10 antibody has proven valuable for identifying genome-wide binding sites of ARR10. The following methodological considerations are critical:

• Experimental system preparation:

  • Use Arabidopsis lines with controlled ARR10 expression (e.g., lines with ectopic overexpression of ARR10)

  • Include appropriate controls (wild-type and arr10 mutant plants)

  • Treat samples with cytokinin to induce ARR10 binding to DNA, as binding is cytokinin-dependent

• ChIP-seq procedure:

  • Fix protein-DNA complexes efficiently with appropriate crosslinking agent

  • Optimize sonication parameters for plant chromatin fragmentation

  • Perform immunoprecipitation with RR10 antibody at validated concentrations

  • Include appropriate negative controls (non-specific IgG, no-antibody controls)

  • Prepare sequencing libraries following standard protocols

• Data analysis:

  • Map sequencing reads to the reference genome

  • Identify ARR10 binding sites, which are typically enriched near transcriptional start sites

  • Validate binding motifs using protein-binding microarrays

  • Integrate with transcriptomic data to identify direct target genes

This approach has successfully identified WUSCHEL as a direct target of ARR10, with cytokinin-enhanced expression resulting in enhanced shoot formation in tissue culture .

What controls and validation steps are essential when using RR10 antibody in immunoassays?

To ensure reliable and reproducible results when using RR10 antibody, incorporate these critical controls and validation steps:

• Negative controls:

  • Samples without primary antibody processing (procedural control)

  • Pre-immune serum (antibody specificity control)

  • Competing peptide controls (binding specificity verification)

  • Samples from arr10 knockout/knockdown plants (genetic validation)

• Positive controls:

  • Wild-type Arabidopsis tissues known to express ARR10

  • Recombinant ARR10 protein (if available)

  • Cytokinin-treated samples (for induction verification)

• Technical validation:

  • For phospho-specific detection, include 10 μg/ml of non-phospho peptide per 2 μg/ml antibody

  • Perform western blot validation of antibody specificity before immunohistochemistry

  • Verify expected molecular weight (approximately 45 kD for ARR10)

  • Compare staining patterns with published ARR10 expression patterns

Implementing these controls ensures that observed signals genuinely represent ARR10 protein rather than non-specific or background interactions.

How does ARR10 function within the cytokinin signaling pathway?

ARR10 is a type-B Arabidopsis Response Regulator that functions as a DNA-binding transcription factor within the cytokinin signal transduction pathway. Research findings demonstrate:

• ARR10 acts downstream of cytokinin receptors (AHKs) and histidine phosphotransfer proteins (AHPs) in a multi-step phosphorelay system

• It contains a receiver domain that is activated by phosphorylation and a DNA-binding output domain

• Upon cytokinin stimulus, ARR10 binds to specific promoter regions of target genes

• It functions redundantly with other type-B ARRs, particularly ARR1 and ARR12, to mediate primary cytokinin responses

The arr1,10,12 triple mutant exhibits phenotypes highly analogous to those observed for certain ahk2 ahk3 ahk4/cre1 triple mutants, which have virtually no cytokinin receptor function, indicating the essential role of these three ARRs in cytokinin signaling .

What is the relationship between ARR10 and drought tolerance mechanisms in plants?

Research using the RR10 antibody and genetic studies have revealed ARR10's significant role in drought response:

• ARR10, together with ARR1 and ARR12, negatively and redundantly regulates plant drought responses

• The arr1,10,12 triple mutant shows significantly enhanced drought tolerance compared to wild-type plants, as evidenced by:

  • Higher relative water content during drought stress

  • Improved survival rate on drying soil

  • Enhanced cell membrane integrity (lower electrolyte leakage)

  • Increased anthocyanin biosynthesis (protective mechanism)

  • ABA hypersensitivity

  • Reduced stomatal aperture but unaltered stomatal density

• ARR10 expression is down-regulated in both shoots (>twofold) and roots (>twofold) under dehydration conditions

These findings suggest that plants down-regulate ARR10 as an adaptive mechanism to survive drought, indicating that repression of cytokinin signaling is a strategy plants use to cope with water deficit .

How can RR10 antibody be used to investigate ARR10's role in various plant tissues?

The RR10 antibody enables tissue-specific and cell-type-specific investigation of ARR10 function through multiple approaches:

• Tissue-specific expression analysis:

  • Immunohistochemistry of different plant organs (roots, shoots, leaves, flowers)

  • Western blot analysis of protein extracts from different tissues

  • Correlation with ARR10 mRNA expression patterns

• Developmental regulation:

  • Temporal studies across plant development stages

  • Analysis during specific developmental transitions

  • Correlation with cytokinin response during organogenesis

• Stress response localization:

  • Comparative analysis under normal and stress conditions (drought, heat, salt)

  • Co-localization with stress response markers

  • Dynamic changes in ARR10 phosphorylation state under stress

Research has shown differential expression patterns of ARR10 in shoots versus roots, with specific responses to dehydration and ABA treatments , highlighting the importance of tissue-specific analysis of ARR10 function.

How does ARR10 DNA binding change in response to cytokinin treatment?

ChIP-seq studies using the RR10 antibody have revealed fundamental insights into ARR10's DNA binding dynamics:

• Binding of ARR10 to DNA is strongly induced by cytokinin treatment

• ARR10 binding sites are enriched toward transcriptional start sites for both cytokinin-induced and cytokinin-repressed genes

• Three type-B ARR DNA-binding motifs have been identified and are enriched at ARR10 binding sites

• Upon cytokinin treatment, the three different B-ARRs (including ARR10) converge to exhibit identical DNA binding signatures (AGATHY, where H represents A/T/C and Y represents T/C)

• This suggests cytokinin may regulate not only the binding activity but also the binding specificity of B-ARR family members

These findings provide mechanistic insights into how cytokinin signaling achieves both specificity and diversity in transcriptional responses.

What complementary approaches can validate findings obtained with RR10 antibody?

• Genetic validation:

  • Analyze arr10 single, double (arr1,10 or arr10,12), and triple (arr1,10,12) mutants

  • Use ARR10 overexpression lines for gain-of-function studies

  • Employ inducible or tissue-specific expression systems

• Molecular validation:

  • Perform RNA-seq or microarray analysis to correlate binding with gene expression

  • Use protein-binding microarrays to validate DNA binding motifs

  • Employ yeast one-hybrid or electrophoretic mobility shift assays

• Functional validation:

  • Conduct phenotypic analyses under various conditions (normal growth, drought stress)

  • Measure physiological parameters (water content, membrane integrity)

  • Analyze hormone responses (cytokinin, ABA sensitivity)

Comparative transcriptome analysis of arr1,10,12 and wild-type plants under both normal and dehydration conditions has revealed a cytokinin signaling-mediated network controlling plant adaptation to drought via numerous dehydration/drought- and/or ABA-responsive genes .

How do ARR10 target genes differ between normal growth and stress conditions?

Research using RR10 antibody and transcriptomic approaches has identified distinct ARR10 target gene networks under different conditions:

• Under normal growth conditions:

  • ARR10 regulates genes involved in shoot apical meristem maintenance (e.g., WUSCHEL)

  • Target genes include those controlling cell division and expansion

  • Many targets overlap with other hormone signaling pathways, particularly auxin

• Under drought stress conditions:

  • Comparative transcriptome analysis identified 1,414 up-regulated and 817 down-regulated genes in arr1,10,12 versus wild-type under unstressed conditions

  • Under dehydration, 676 genes were induced and 766 genes were repressed in the mutant compared to wild-type

  • Long-term dehydration (4h) showed more differentially expressed genes than short-term dehydration (2h)

• Functional categories of target genes:

  • Genes providing osmotic adjustment

  • Genes protecting cellular and membrane structures

  • Anthocyanin biosynthesis pathway genes

  • ABA-responsive genes

  • Genes regulating stomatal function

This differential regulation highlights the context-dependent role of ARR10 in coordinating growth versus stress responses in plants.

What are common challenges in RR10 antibody immunostaining and how can they be addressed?

When using RR10 antibody for immunohistochemistry in plant tissues, researchers often encounter these challenges:

For phospho-specific detection, always include 10 μg/ml of the non-phospho peptide per 2 μg/ml of antibody to increase specificity .

How can researchers overcome protein extraction challenges when studying ARR10?

Efficient extraction of ARR10 protein from plant tissues requires careful consideration of these factors:

• Buffer optimization:

  • Use buffers containing phosphatase inhibitors to preserve phosphorylation state

  • Include protease inhibitor cocktail to prevent degradation

  • Optimize detergent concentration for membrane-associated fractions

• Extraction procedure:

  • Rapid freezing of tissue in liquid nitrogen is essential

  • Maintain cold temperatures throughout extraction

  • Consider subcellular fractionation to enrich nuclear proteins

• Sample preparation for immunoblotting:

  • Optimize protein loading (typically 20-50 μg per lane)

  • Include positive controls (e.g., cytokinin-treated samples)

  • Compare wild-type and arr10 mutant samples in parallel

Efficient extraction protocols are critical for subsequent applications such as western blotting, immunoprecipitation, and ChIP-seq experiments using the RR10 antibody.

What factors should be considered when interpreting ChIP-seq data obtained with RR10 antibody?

When analyzing ARR10 ChIP-seq results, consider these important factors to ensure accurate interpretation:

• Technical considerations:

  • Antibody specificity (validate with appropriate controls)

  • Signal-to-noise ratio (compare to input and IgG controls)

  • Sequencing depth (sufficient coverage for peak detection)

  • Reproducibility between biological replicates

• Biological interpretations:

  • Enrichment of binding near transcriptional start sites is expected

  • Presence of validated ARR10 binding motifs (AGATHY)

  • Increased binding upon cytokinin treatment

  • Correlation with gene expression changes

• Integrative analysis:

  • Compare binding profiles in different tissues or conditions

  • Integrate with transcriptomic data to identify direct targets

  • Consider redundancy with other type-B ARRs (ARR1, ARR12)

  • Evaluate evolutionary conservation of binding sites across species

Research has shown that ARR10 binding is highly cytokinin-dependent, with binding sites enriched toward transcriptional start sites for both induced and repressed genes .