FANCL Antibody

What is FANCL and what is its role in cellular processes?

FANCL functions as a ubiquitin E3 ligase within the Fanconi anemia (FA) nuclear core complex, which consists of multiple proteins including FANCA, B, C, E, F, G, L, and M. Its primary function is mediating the monoubiquitination of FANCD2 and FANCI, which represents a pivotal step in the DNA damage response pathway . This ubiquitination is essential for recruiting repair proteins to DNA damage sites, facilitating the repair process and maintaining genomic stability . Phosphorylation of FANCL and other FA proteins appears critical for their proper function within the FA pathway, highlighting the importance of post-translational modifications . Beyond DNA repair, FANCL is involved in primordial germ cell proliferation during embryonic development and may form testis-specific networks with other proteins in adult testis . Its wide expression across multiple tissues indicates broader physiological roles beyond the FA pathway .

What types of FANCL antibodies are currently available for research?

Several types of FANCL antibodies are available for research applications:

• Mouse monoclonal antibodies: The B-11 antibody (IgG2b kappa light chain) detects FANCL in mouse, rat, and human samples through multiple applications including western blotting, immunoprecipitation, immunofluorescence, immunohistochemistry, and ELISA .

• Rabbit polyclonal antibodies: Generated against full-length human FANCL protein (amino acids 1-375) or specific regions, these antibodies offer flexibility across different applications .

• Mouse monoclonal antibody (66639-1-Ig): Specifically targets human FANCL in applications like Western blotting and immunofluorescence with demonstrated reactivity in HeLa and HEK-293 cells .

These antibodies are available in various forms including non-conjugated formats and conjugated versions with agarose, horseradish peroxidase (HRP), phycoerythrin (PE), fluorescein isothiocyanate (FITC), and multiple Alexa Fluor® conjugates to suit different experimental needs .

How can I validate the specificity of FANCL antibodies in my experimental system?

Validating FANCL antibody specificity requires multiple complementary approaches:

• FANCL knockdown/knockout validation: Compare antibody detection between wild-type samples and those with reduced or eliminated FANCL expression. This represents the gold standard for antibody validation .

• Expression system validation: Use transfection approaches with tagged FANCL constructs (such as HA-FANCL) to confirm antibody specificity. For example, researchers have validated FANCL antibodies by analyzing transiently expressed HA-FANCL fusion proteins through immunoblotting with both FANCL-specific antibodies and HA antibodies .

• Molecular weight confirmation: FANCL typically appears at 41-43 kDa on Western blots, with some sources reporting a truncated form at approximately 28 kDa . Confirming the correct molecular weight helps verify specificity.

• Cross-reactivity assessment: When working with non-human samples, verify cross-reactivity through sequence alignment of the epitope region and validation with positive control samples from the target species .

• Multiple antibody validation: Using antibodies targeting different FANCL epitopes provides stronger evidence of specific detection when results are concordant.

What are the optimal conditions for detecting FANCL using Western blotting?

For optimal FANCL detection via Western blotting:

• Sample preparation:

  • Use lysis buffers containing protease inhibitors to prevent degradation

  • Include reducing agents (DTT or β-mercaptoethanol) to break disulfide bonds

  • Heat samples at 95°C for 5 minutes in SDS sample buffer

• Antibody selection and dilution:

  • Mouse monoclonal antibodies (66639-1-Ig): Use at 1:1000-1:3000 dilution

  • Polyclonal antibodies: Dilutions may vary; follow manufacturer recommendations

• Controls:

  • Positive controls: HeLa or HEK-293 cell lysates (confirmed to express FANCL)

  • Negative controls: FANCL knockout/knockdown samples

  • Loading controls: Standard housekeeping proteins (β-actin, GAPDH)

• Detection:

  • FANCL should be visualized at 41-43 kDa for the full-length protein

  • Secondary antibody selection should match the host species of the primary antibody

• Troubleshooting:

  • Multiple bands may indicate degradation or post-translational modifications

  • Absence of signal may require longer exposure times or antibody concentration adjustments

  • High background may necessitate more stringent washing steps

How can FANCL antibodies be effectively used in immunoprecipitation studies?

For successful immunoprecipitation with FANCL antibodies:

• Antibody selection:

  • Use antibodies specifically validated for immunoprecipitation

  • Agarose-conjugated FANCL antibodies (such as sc-137067 AC) can simplify the procedure

  • For non-conjugated antibodies, protein A/G beads can capture antibody-protein complexes

• Protocol considerations:

  • Use gentler lysis buffers (e.g., 50 mM Tris, pH 8, 250 mM NaCl with 2 mM DTT) to preserve protein-protein interactions

  • Pre-clear lysates with protein A/G beads to reduce non-specific binding

  • Incubate antibody with lysate overnight at 4°C for maximal binding

  • Use 100 μl of equilibrated Ni²⁺-nitrilotriacetic acid-agarose or anti-FLAG affinity gel for appropriate tagged proteins

  • Wash extensively with assay buffer to remove non-specific interactions

• Controls:

  • Include an isotype control antibody (matching the FANCL antibody host species)

  • Use lysate from FANCL-depleted cells as a negative control

  • Consider tagged FANCL constructs as positive controls and for validation

• Analysis:

  • Assess immunoprecipitation efficiency by Western blotting a portion of the IP sample

  • Probe for co-immunoprecipitated proteins to study FANCL interactions

  • For interaction studies, 225 nM FLAG-FANCI can be added with 454 nM human FANCL central domain or mutants

What are the best practices for immunofluorescence detection of FANCL?

For optimal immunofluorescence detection of FANCL:

• Sample preparation:

  • Fix cells with 4% paraformaldehyde (10-15 minutes) to preserve cellular architecture

  • Permeabilize with 0.1-0.5% Triton X-100 (5-10 minutes) to allow antibody access

  • Block with 5% normal serum from the secondary antibody species to reduce background

• Antibody application:

  • For mouse monoclonal antibodies (66639-1-Ig): Use at 1:400-1:1600 dilution

  • Incubate overnight at 4°C or 1-2 hours at room temperature

  • Use fluorophore-conjugated secondary antibodies specific to the primary antibody host

  • HeLa cells have been successfully used for FANCL immunofluorescence studies

• Controls:

  • Include a primary antibody omission control to assess background

  • Use FANCL-depleted cells as negative controls

  • Consider cells transfected with fluorescently-tagged FANCL as positive controls

• Imaging:

  • FANCL typically shows nuclear localization, particularly following DNA damage

  • Co-staining with other FA pathway proteins can reveal co-localization at repair foci

  • Confocal microscopy provides optimal resolution for nuclear staining patterns

• Analysis:

  • Quantify fluorescence intensity to assess expression levels

  • Track FANCL localization changes in response to DNA damage or cell cycle phases

  • Co-localization analysis with other proteins can reveal functional interactions

How can FANCL antibodies be used to study the Fanconi anemia pathway and DNA repair?

FANCL antibodies provide powerful tools for investigating the FA pathway:

• FANCD2 monoubiquitination analysis:

  • As the E3 ligase responsible for FANCD2 monoubiquitination, FANCL is a central component of the FA pathway

  • Immunoprecipitate FANCL and probe for interaction with FANCD2 before and after DNA damage

  • Analyze FANCD2 monoubiquitination status in wild-type versus FANCL-depleted cells

  • Thioester charge assays can be used to assess FANCL's E3 ligase activity, using 2 μM E2 or human central domain charged with 50 μM HA-Ub using 150 nM E1

• FA complex formation studies:

  • Structural analysis of human FANCL and its interaction with other FA proteins helps elucidate complex formation mechanisms

  • Co-immunoprecipitation with FANCL antibodies can identify interactions with other FA proteins

  • Compare complex formation under normal conditions versus after DNA damage induction

• DNA damage response dynamics:

  • Track FANCL localization to DNA damage sites using immunofluorescence

  • Analyze temporal changes in FANCL expression, modification, and interactions after damage

  • Study recruitment kinetics to understand the sequence of events in the FA pathway activation

• Structure-function analysis:

  • Compare wild-type FANCL with mutant variants to identify functional domains

  • FANCL central domain has been specifically studied for its role in protein interactions

  • Use FANCL antibodies to assess the impact of mutations on protein stability and interactions

What considerations are important when studying FANCL across different species?

When studying FANCL across species, several considerations are important:

• Antibody cross-reactivity:

  • The B-11 mouse monoclonal antibody has demonstrated reactivity with mouse, rat, and human FANCL

  • Other antibodies may have limited species cross-reactivity, requiring careful validation

  • Sequence conservation at the epitope region predicts cross-reactivity potential

• Evolutionary conservation:

  • FANCL function is conserved across species, including humans and Drosophila melanogaster

  • Structural comparisons between human and Drosophila FANCL reveal important evolutionary insights

  • Species-specific differences in size or post-translational modifications may affect detection

• Experimental validation:

  • When using antibodies in non-validated species, perform careful controls

  • Consider using recombinant FANCL from the species of interest as a positive control

  • Compare results with orthogonal methods like mRNA analysis

• Functional studies:

  • While the core function of FANCL in the FA pathway is conserved, species-specific interactions may exist

  • Cross-species complementation studies can reveal functional conservation

  • Model organisms provide valuable insights, as shown by studies in mice where FANCL is widely expressed across tissues

How can FANCL antibodies help investigate post-translational modifications of FANCL?

FANCL antibodies are valuable tools for studying post-translational modifications:

• Phosphorylation analysis:

  • Phosphorylation of FANCL and other FA proteins is critical for their function within the FA pathway

  • Immunoprecipitate FANCL using specific antibodies and analyze by phospho-specific detection methods

  • Compare phosphorylation status before and after DNA damage to identify regulatory events

• Ubiquitination studies:

  • FANCL itself may undergo ubiquitination as part of auto-regulation

  • Use denaturing immunoprecipitation to distinguish covalent ubiquitin attachment

  • Analyze ubiquitin chain types to understand the functional consequences

• Experimental approaches:

  • Combine FANCL immunoprecipitation with mass spectrometry to identify modification sites

  • Use phosphatase or deubiquitinase treatments to confirm modification types

  • Create modification-specific mutants to study functional impacts

• Dynamic regulation:

  • Study how modifications change during cell cycle progression or after DNA damage

  • Analyze the interplay between different types of modifications

  • Identify enzymes responsible for adding or removing modifications

What are common issues encountered when using FANCL antibodies and how can they be resolved?

Common challenges and solutions when working with FANCL antibodies:

• Weak or absent signal:

  • Increase antibody concentration or incubation time

  • Verify FANCL expression in your sample (HeLa and HEK-293 cells are known positives)

  • Check antibody storage conditions and expiration date

  • Try different detection methods or more sensitive detection reagents

• Multiple bands or high background:

  • Increase antibody dilution to reduce non-specific binding

  • Add additional blocking steps or increase blocking agent concentration

  • Use freshly prepared samples with complete protease inhibitors to prevent degradation

  • Increase washing duration and number of washes

• Inconsistent results:

  • Standardize sample preparation and handling procedures

  • Use the same antibody lot for related experiments

  • Include positive controls in every experiment

  • Normalize to loading controls for quantitative comparisons

• Species cross-reactivity issues:

  • Verify antibody reactivity with your species of interest

  • Test multiple antibodies targeting different epitopes

  • Consider using recombinant FANCL as a positive control

• Post-translational modifications affecting detection:

  • Be aware that phosphorylation or ubiquitination may alter antibody binding

  • Use multiple antibodies targeting different epitopes

  • Consider treatment with phosphatases or deubiquitinases as controls

What are the optimal storage conditions for maintaining FANCL antibody activity?

To maintain FANCL antibody performance:

• Storage temperature:

  • Store at -20°C for long-term storage, as recommended for antibodies like 66639-1-Ig

  • Avoid repeated freeze-thaw cycles by preparing small aliquots

  • For short-term use (1-2 weeks), 4°C storage may be acceptable

• Storage buffer:

  • Most FANCL antibodies are supplied in PBS with 0.02% sodium azide and 50% glycerol (pH 7.3)

  • This formulation provides stability and prevents microbial growth

  • Do not dilute stock antibody unless preparing working aliquots

• Handling practices:

  • Thaw antibodies completely before use and mix gently by pipetting or flicking

  • Avoid vortexing, which can denature antibodies

  • Use clean, DNase/RNase-free tubes for aliquoting

  • Keep antibodies on ice when in use

• Conjugated antibodies:

  • Fluorophore-conjugated antibodies should be protected from light

  • HRP-conjugated antibodies may have shorter shelf lives than unconjugated versions

  • Follow specific storage recommendations for each conjugate type

• Working dilutions:

  • Prepare fresh working dilutions for each experiment

  • If storage of diluted antibody is necessary, add carrier protein (BSA) at 0.1-1%

  • Store diluted antibodies at 4°C for no more than 1-2 weeks

How can FANCL antibodies be used to study tissue-specific expression patterns?

FANCL antibodies enable detailed tissue expression analysis:

• Western blot tissue profiling:

  • FANCL has been detected in brain, muscle, heart, lung, liver, spleen, kidney, testis, ovary, and uterus using Western blotting with FANCL-specific antibodies

  • Prepare standardized tissue lysates with complete protease inhibitors

  • Use consistent loading (30-50 μg total protein) and normalize to housekeeping proteins

  • Compare relative expression levels across tissues to identify enrichment patterns

• Immunohistochemistry applications:

  • Formalin-fixed paraffin-embedded or frozen tissue sections can be probed with FANCL antibodies

  • Optimize antigen retrieval methods for each tissue type

  • Cell type-specific expression can reveal functional specialization

  • Quantitative image analysis allows objective comparison between tissues

• Developmental expression:

  • Study FANCL expression across developmental stages using tissue samples from different timepoints

  • Particularly relevant for investigating FANCL's role in primordial germ cell proliferation

  • Combine with markers of differentiation to correlate FANCL expression with developmental processes

• Disease-associated changes:

  • Compare FANCL expression between normal and pathological tissues

  • Correlate expression patterns with disease progression or severity

  • Identify cell types with altered FANCL expression in disease states

What are the considerations for using FANCL antibodies in high-throughput screening applications?

For high-throughput applications with FANCL antibodies:

• Antibody selection criteria:

  • Choose antibodies with high specificity and low background

  • Monoclonal antibodies often provide better consistency across large sample sets

  • Validate antibody performance in your specific assay format before scaling up

• Assay development:

  • Optimize antibody concentration to balance signal strength and specificity

  • Determine the linear detection range for quantitative applications

  • Establish clear positive and negative controls for quality control

  • Validate automated protocols against manual methods

• Platform-specific considerations:

  • Microarray applications: Consider antibody cross-reactivity carefully

  • ELISA: Optimize coating, blocking, and detection conditions

  • Automated immunofluorescence: Ensure consistent fixation and permeabilization

  • Flow cytometry: Validate intracellular staining protocols for FANCL detection

• Data analysis approaches:

  • Implement robust normalization methods to control for technical variation

  • Establish clear thresholds for positive/negative determination

  • Consider machine learning approaches for pattern recognition in complex datasets

  • Validate hits with orthogonal methods

• Quality control measures:

  • Include technical and biological replicates

  • Use plate layout designs that control for edge effects and drift

  • Monitor assay performance with consistent control samples