cfap77 Antibody

What is CFAP77 and why is it significant in research?

CFAP77 (Cilia and Flagella Associated Protein 77), also known as C9orf171 or chromosome 9 open reading frame 171, is a protein essential for sperm progressive motility and male fertility. It forms a ternary subcomplex with CCDC105 and TEX43 at the outer junction (OJ) regions of doublet microtubules (DMTs) in sperm flagella. This subcomplex plays a critical role in maintaining the structural integrity of the A-B tubule connection in DMTs, which is fundamental for proper sperm motility. Research has shown that knockout of this gene in mice results in complete male infertility due to severe defects in sperm progressive motility, highlighting its significance in reproductive biology research .

What are the validated applications for CFAP77 antibody?

The commercially available CFAP77 polyclonal antibody has been validated for several key research applications including Western Blot (at 0.4 μg/ml concentration), standard Immunohistochemistry, and Immunohistochemistry on Paraffin-embedded tissues (at dilutions of 1:50 to 1:200). These applications allow researchers to detect and localize CFAP77 protein in various experimental contexts, particularly in human samples . For specialized research applications such as studying protein-protein interactions, the antibody has demonstrated utility in co-immunoprecipitation (Co-IP) experiments when investigating the CFAP77-CCDC105-TEX43 subcomplex formation .

What technical specifications should researchers know about CFAP77 antibody?

The commercially available CFAP77 antibody is a rabbit polyclonal antibody that has been affinity purified and is typically supplied in PBS (pH 7.2) with 40% glycerol and 0.02% sodium azide for stability. It specifically targets the CFAP77 protein (also known as C9orf171) in human samples. The antibody was developed against a recombinant protein corresponding to a specific amino acid sequence: EKKQKVVLGKLYETRSSQLRKYKPPVKLDTLWHMPHFQKVGRHLDTFPTEADRQRALKAHREECAVRQGTLRMGNYTH. The specificity of the antibody has been verified on a protein array containing the target protein plus 383 other non-specific proteins, ensuring reliable detection in experimental settings .

How can CFAP77 antibody be used to investigate male infertility mechanisms?

CFAP77 antibody serves as a crucial tool for investigating the molecular basis of male infertility. Researchers can employ the antibody in Western blot analyses of sperm samples from infertile patients to assess CFAP77 expression levels compared to fertile controls. Recent studies utilizing CFAP77-knockout mouse models have definitively demonstrated that the absence of CFAP77 results in complete male infertility due to severe defects in sperm progressive motility. Immunohistochemistry with CFAP77 antibody on testicular biopsies can help visualize the localization pattern of the protein within the developing sperm cells and identify potential abnormalities in protein distribution that may correlate with fertility issues .

How does the CFAP77-CCDC105-TEX43 subcomplex function in sperm motility?

The CFAP77-CCDC105-TEX43 ternary subcomplex plays a critical role in maintaining the structural integrity of doublet microtubules (DMTs) in sperm flagella. Specifically, this subcomplex localizes to the outer junction (OJ) regions of DMTs and is essential for the proper connection between the A and B tubules. Research using CFAP77 antibody in combination with structural biology techniques has revealed that disruption of this subcomplex, as seen in Cfap77-KO mice, causes approximately 45% of DMT-B tubules to open at the OJ regions, compromising the ultrastructure of sperm DMTs. Through co-immunoprecipitation experiments using CFAP77 antibody, researchers have identified key interaction interfaces between CFAP77 and CCDC105, specifically involving the G131-V133 residues of CFAP77 and the M352-G355 residues of CCDC105. Mutation of these residues significantly attenuates the interaction between these proteins, demonstrating their importance in subcomplex formation and stability .

What structural insights about flagellar architecture have been gained using CFAP77 antibody?

CFAP77 antibody has facilitated significant advances in understanding flagellar ultrastructure, particularly through its use in immunolocalization studies complemented by cutting-edge cryo-electron tomography (cryo-ET). By combining immunolocalization data with high-resolution structural techniques, researchers have precisely mapped CFAP77 to the outer junction (OJ) of doublet microtubules in sperm flagella. In Cfap77-knockout mice, cryo-ET imaging revealed notable structural heterogeneity in DMT particles, indicating that CFAP77 is crucial for maintaining consistent flagellar architecture. After sophisticated 3D classification and sub-tomogram averaging approaches, researchers obtained an 8 nm repeat structure of DMTs with a resolution of 24 Å, revealing specific structural defects in the absence of CFAP77. This multidisciplinary approach highlights how antibody-based identification combined with advanced structural biology techniques can provide detailed insights into complex cellular structures that would be unattainable with either approach alone .

What are the optimal conditions for Western blot using CFAP77 antibody?

For optimal Western blot results with CFAP77 antibody, researchers should extract proteins using RIPA lysis buffer containing 1 mM PMSF and 2% (v/w) protease inhibitor cocktail on ice. After centrifugation at 12,000 × g for 10 minutes, collect the supernatant containing the solubilized proteins. For protein separation, a 10% SDS-PAGE gel is recommended. The CFAP77 antibody should be used at a concentration of 0.4 μg/ml (approximately 1:1000-1:2500 dilution depending on stock concentration). For protein extraction specifically from sperm samples (where CFAP77 is highly expressed), careful lysis procedures are essential to overcome the unique structural resilience of sperm cells. Overnight primary antibody incubation at 4°C generally yields the best signal-to-noise ratio. When interpreting results, be aware that CFAP77 has a molecular weight of approximately 31 kDa, but observed band size may vary slightly due to post-translational modifications .

How should immunohistochemistry protocols be optimized for CFAP77 detection?

For immunohistochemistry applications with CFAP77 antibody, both frozen and paraffin-embedded tissue sections can be utilized, with dilutions ranging from 1:50 to 1:200 depending on sample type and detection system. For paraffin-embedded tissues, effective antigen retrieval is critical - heat-induced epitope retrieval using citrate buffer (pH 6.0) for 15-20 minutes is generally effective. When working with reproductive tissues, particularly testis samples, optimization of fixation time is crucial as over-fixation can mask epitopes and reduce antibody accessibility to the target protein. For immunofluorescence applications, counterstaining with DAPI helps visualize nuclei, while co-staining with microtubule markers (such as α-tubulin or acetylated tubulin) can provide valuable context for CFAP77 localization within flagellar structures. Negative controls should include both primary antibody omission and, ideally, samples from Cfap77-knockout models to confirm specificity of staining patterns .

What considerations are important when generating CFAP77 knockout models?

When generating CFAP77 knockout models for research, several critical considerations should be addressed. First, careful selection of target exons is essential - in previous successful studies, exons 2 and 3 of the Cfap77-202 transcript (ENSMUST00000157048) were targeted to generate a 30,988 bp deletion using CRISPR/Cas9 technology. Mouse zygotes were co-injected with Cas9 mRNA and specific sgRNAs, then transferred to pseudopregnant recipients. For genotyping, DNA extracted from tail tissues of 7-day-old offspring should be PCR-amplified using appropriate primers. Western blot analysis using CFAP77 antibody is crucial to confirm complete absence of protein expression in knockout models. When characterizing the phenotype, researchers should conduct comprehensive fertility testing by mating knockout males with wild-type females and tracking pregnancy rates and litter sizes. Additionally, in vitro fertilization assays and detailed semen analysis should be performed to fully assess the impact of CFAP77 deletion on sperm function and fertility outcomes .

How can researchers address non-specific binding issues with CFAP77 antibody?

Non-specific binding can be a significant challenge when working with polyclonal antibodies like the CFAP77 antibody. To minimize this issue, researchers should implement several optimization strategies. First, increase blocking stringency by using 5% BSA or 5% non-fat dry milk in TBS-T for Western blots and immunohistochemistry applications. Consider extending the blocking time to 2 hours at room temperature. Second, optimize antibody concentration through careful titration experiments - while the recommended concentration is 0.4 μg/ml for Western blots and 1:50-1:200 for immunohistochemistry, your specific experimental conditions may require adjustments. Third, increase washing stringency with additional wash steps using TBS-T or PBS-T containing 0.1-0.3% Tween-20. For particularly challenging samples, pre-adsorption of the antibody with non-specific proteins can help reduce background. When interpreting results, always include appropriate negative controls (samples known to be negative for CFAP77 expression) and positive controls (samples with validated CFAP77 expression). The specificity of the commercially available CFAP77 antibody has been verified against 383 non-specific proteins, which should provide confidence in its target specificity when used under optimized conditions .

How should researchers interpret CFAP77 antibody signals in different cell and tissue types?

Interpreting CFAP77 antibody signals requires careful consideration of the biological context. CFAP77 is primarily expressed in ciliated tissues, with particularly high expression in sperm flagella where it plays a critical role in maintaining the structural integrity of doublet microtubules. When examining sperm samples, CFAP77 should localize specifically to the flagellum, with a distinct pattern at the outer junction regions of doublet microtubules. Absence or mislocalization of this pattern could indicate structural abnormalities associated with motility defects. In other ciliated tissues, expression patterns may vary, but should generally correlate with ciliary structures. Quantitative assessment of signal intensity can provide insights into expression levels, but should always be normalized to appropriate housekeeping proteins and compared with proper controls. When analyzing patient samples in fertility research, consideration of patient clinical history and comprehensive semen analysis parameters is essential for contextualizing CFAP77 expression patterns. Researchers should be cautious about interpreting signals in tissues not previously characterized for CFAP77 expression, and validation with multiple techniques (Western blot, IHC, IF) is recommended in such cases .

What are the common pitfalls in co-immunoprecipitation experiments using CFAP77 antibody?

When conducting co-immunoprecipitation (Co-IP) experiments to study CFAP77 interactions, researchers should be aware of several common pitfalls. First, inadequate cell lysis can significantly impact results, particularly when working with sperm cells that have resilient structures - optimization of lysis buffers and conditions is essential. Second, non-specific binding to beads or antibodies can lead to false-positive results; implementation of appropriate pre-clearing steps and the use of isotype controls are critical. Third, the interaction between CFAP77 and its partners (CCDC105 and TEX43) may be sensitive to salt concentration in buffers - testing a range of salt concentrations (150-500 mM) can help optimize detection of true interactions. Fourth, some interactions may be transient or weak; crosslinking prior to lysis can help preserve such interactions. When analyzing results, researchers should confirm findings with reciprocal Co-IPs (i.e., pull down with CFAP77 antibody and probe for partners, then pull down with partner antibodies and probe for CFAP77). Finally, validation of interactions identified by Co-IP should be performed using complementary techniques such as proximity ligation assay or FRET, particularly when investigating novel interaction partners beyond the established CFAP77-CCDC105-TEX43 subcomplex .

What have recent studies revealed about CFAP77's role in human fertility disorders?

Recent research utilizing CFAP77 antibody has significantly advanced our understanding of human fertility disorders. Studies with Cfap77-knockout mice have definitively established that CFAP77 deficiency results in complete male infertility due to severe sperm motility defects. These knockout models demonstrate that sperm from affected males have structural abnormalities in approximately 45% of DMT-B tubules at the outer junction regions, compromising flagellar architecture and function. This finding has important translational implications, suggesting that CFAP77 mutations could be an undiagnosed cause of asthenozoospermia (poor sperm motility) or oligoasthenozoospermia in human male infertility cases. The identification of the critical CFAP77-CCDC105-TEX43 subcomplex at the outer junction provides a new molecular target for diagnostic development. Future clinical research should focus on screening infertile men for CFAP77 mutations or expression abnormalities, particularly those presenting with sperm motility defects of unknown etiology. The development of targeted therapeutic approaches to address CFAP77-related fertility issues represents an important frontier in reproductive medicine research .

How is CFAP77 research contributing to our understanding of ciliopathies beyond fertility?

While CFAP77 research has primarily focused on its role in sperm flagella and male fertility, emerging evidence suggests potential broader implications for other ciliated tissues and ciliopathy disorders. The fundamental role of CFAP77 in maintaining microtubule doublet structural integrity in sperm flagella raises important questions about its potential function in other ciliated cells throughout the body. Using the CFAP77 antibody to examine protein expression and localization in various ciliated tissues could reveal previously unrecognized roles in primary cilia or motile cilia of other organs. This could potentially link CFAP77 dysfunction to other ciliopathies affecting respiratory, renal, or neurological systems. The structural insights gained from cryo-electron tomography studies of CFAP77-deficient sperm also provide valuable information about fundamental ciliary architecture that may be applicable across different ciliary types. Future research should explore CFAP77 expression patterns across diverse ciliated tissues and investigate potential associations between CFAP77 variants and ciliopathy phenotypes beyond male infertility. This expanded focus could potentially identify CFAP77 as a new candidate gene for screening in patients with suspected ciliopathy disorders .

What methodological advances are enhancing CFAP77 antibody applications in structural biology?

The integration of CFAP77 antibody-based techniques with advanced structural biology methods represents a frontier in reproductive and ciliary research. Recent studies have combined traditional antibody applications with cutting-edge approaches like cryo-focused ion beam thinning (cryo-FIB) and cryo-electron tomography (cryo-ET) to achieve unprecedented insights into flagellar ultrastructure. In these advanced applications, sperm samples are first characterized using CFAP77 antibody in immunolocalization studies to confirm protein expression and distribution. The samples are then frozen on grids and milled to approximately 200 nm thickness using cryo-FIB technology before cryo-ET data collection. This combined approach has enabled researchers to resolve the in situ structure of doublet microtubules using sub-tomogram averaging techniques, achieving structural resolutions of approximately 24 Å at an 8 nm repeat. These methodological advances have revealed critical details about how the CFAP77-CCDC105-TEX43 subcomplex stabilizes the outer junction of microtubule doublets. Future methodological developments may include correlative light and electron microscopy approaches that directly link CFAP77 immunofluorescence signals with nanoscale structural features, further enhancing our understanding of this protein's functional significance in ciliary architecture .