XPB2 Antibody
Description
Introduction to XAB2 Antibody
XAB2 (XPA-binding protein 2) is a multifunctional protein involved in transcription-coupled DNA repair (TCR) and pre-mRNA splicing . Antibodies targeting XAB2 are critical tools for studying its role in these processes, particularly in understanding its interactions with XPA (Xeroderma Pigmentosum group A protein) and spliceosome components . These antibodies enable researchers to detect endogenous XAB2 levels, map its cellular localization, and investigate its functional mechanisms in genomic stability and RNA processing.
Structure and Function of XAB2 Protein
XAB2 is a 90–95 kDa protein encoded by the XAB2 gene (also known as SYF1 or KIAA1177) and is conserved across eukaryotes . Key structural and functional features include:
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Domain Organization: While the exact domain structure remains under study, XAB2 interacts with XPA through a central region critical for DNA repair .
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Spliceosome Component: XAB2 is part of the spliceosome complex, facilitating pre-mRNA splicing by coordinating spliceosomal assembly .
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DNA Repair Role: XAB2 binds XPA, a core nucleotide excision repair (NER) factor, to mediate transcription-coupled repair of DNA lesions .
Role in DNA Repair and Transcription
XAB2 operates at the intersection of DNA repair and RNA splicing:
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Transcription-Coupled Repair (TCR): XAB2 recruits repair factors to RNA polymerase II-stalled sites, resolving transcription-blocking DNA lesions .
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Spliceosome Regulation: As a pre-mRNA splicing factor, XAB2 ensures proper spliceosome assembly and efficiency, impacting gene expression .
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Disease Links: Mutations in XAB2 or its interactors are implicated in genomic instability disorders, though direct human pathologies are still under investigation .
Research Findings and Clinical Implications
Recent studies highlight XAB2’s diverse roles:
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TFIIH Interaction: XAB2’s recruitment to DNA damage sites depends on TFIIH, a transcription/repair complex .
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Knockdown Effects: Depleting XAB2 disrupts spliceosome activity and sensitizes cells to DNA-damaging agents, underscoring its dual functionality .
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Therapeutic Potential: Targeting XAB2 could modulate spliceosome activity in cancers or enhance DNA repair in neurodegenerative diseases .
Antibody Characteristics and Applications
XAB2 antibodies (e.g., Thermo Fisher PA5-100368, Abcam ab248603) are validated for specificity and utility in key assays:
Table 2: XAB2 Protein Features
Key Research Applications
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Mechanistic Studies: XAB2 antibodies are used to elucidate its role in TCR and spliceosome dynamics .
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Disease Models: Investigated in cancer and neurodegeneration for links to defective DNA repair/splicing .
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Biomarker Potential: XAB2 expression levels may correlate with therapeutic resistance in chemotherapy .
Product Specs
Target Background
Q&A
How does XPB function in transcription-coupled repair (TCR), and what experimental approaches validate its role?
XPB, a subunit of the TFIIH complex, facilitates RNA polymerase II backtracking during TCR to allow access to DNA damage sites. Key methodologies include:
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Chromatin immunoprecipitation (ChIP) to track XPB recruitment at UV-induced DNA lesions .
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CRISPR knockouts in cell lines (e.g., ACH-2 or OM-10.1) to assess transcriptional arrest post-DNA damage .
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Co-localization assays with antibodies against XPB and repair proteins (e.g., XPC, XPF) to study dynamic interactions .
What factors contribute to contradictory data on XPB degradation efficacy across studies?
Discrepancies in XPB degradation levels (e.g., 95% in OM-10.1 vs. 81% in ACH-2 cells) may arise from:
How can researchers resolve non-specific binding of XPB antibodies in immunoprecipitation (IP)?
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Pre-clearing lysates with protein A/G beads to reduce non-target interactions.
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Validate antibody specificity using knockout cell lines (e.g., XPB-deficient fibroblasts) .
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Competitive peptide assays with synthetic XPB epitopes (e.g., aa 800–C-terminal) to confirm signal loss .
What advanced techniques are used to study XPB’s role in HIV-1 latency reversal?
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Single-molecule RNA FISH to quantify HIV-1 transcriptional bursts after XPB inhibition .
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Dose-response profiling with SP (IC₅₀ = 1.95 µM in ACH-2 cells) to correlate XPB degradation with viral capsid (p24) reduction .
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Longitudinal RNA-seq to track splice variants in HIV-1 proviruses under XPB modulation .
How do XPB mutations affect its interaction with other nucleotide excision repair (NER) proteins?
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Severe XPB mutations (e.g., C-terminal truncations) delay recruitment of XPF and XPD to UV damage sites, shown via:
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Mild mutations (e.g., missense) partially retain repair function but reduce transcriptional fidelity .
What controls are critical for interpreting XPB antibody-based assays?
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Internal controls: Use housekeeping proteins (e.g., β-actin) for Western blot normalization .
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Isotype controls: Rule out nonspecific IgG binding in flow cytometry or IP .
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Damage induction controls: Include UV-irradiated vs. untreated cells in TCR studies .
How can computational modeling improve XPB antibody validation workflows?
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Epitope mapping tools (e.g., PyMOL) to predict antibody-antigen binding sites (e.g., aa 800–C-terminal) .
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Machine learning frameworks to analyze phage display data and optimize antibody specificity .
