Recombinant Xenopus laevis Cadherin-1 (cdh1)
Description
Developmental Expression Patterns of Cadherin-1 in Xenopus laevis
Understanding the native expression patterns of Cadherin-1 in Xenopus laevis provides critical context for applications of the recombinant protein. Unlike mammalian homologs, Xenopus E-cadherin exhibits distinctive temporal and spatial expression during embryonic development, making it a fascinating subject for comparative developmental studies.
Temporal Expression During Embryogenesis
Xenopus laevis E-cadherin displays a unique temporal expression pattern that differs significantly from its mammalian counterparts. While E-cadherin is present in early mouse embryos, it is notably absent in Xenopus eggs and early blastula stages . Immunological studies have determined that detectable E-cadherin accumulation begins just before gastrulation at stage 9½ and increases rapidly through the end of gastrulation (stage 15) . Some research more specifically identifies initial detection in the ectoderm of late gastrulas (stage 13-13.5 Nieuwkoop and Faber) .
This temporal pattern suggests that other calcium-dependent adhesion molecules, possibly other members of the cadherin family, are responsible for mediating Ca²⁺-dependent adhesion between cleavage-stage Xenopus blastomeres . Indeed, additional research has identified other cadherins present during early Xenopus development, including EP-cadherin, which is encoded by maternal transcripts and detected in oocytes and unfertilized eggs . EP-cadherin appears to be one of the major cadherins present before the midblastula transition (MBT) .
Spatial Distribution in Embryonic Tissues
The spatial distribution of E-cadherin in Xenopus embryos also displays distinctive patterns:
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In stage 15 embryos, E-cadherin is specifically localized to ectoderm, with no detectable expression in mesoderm or endoderm .
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Within the ectoderm, which consists of two cell layers at this stage, the outer cell layer shows intense staining localized to the basolateral plasma membrane, while the inner cell layer exhibits lower staining levels .
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A more detailed analysis reveals that both the external and sensory layers of the non-neural ectoderm accumulate high levels of E-cadherin, while the ectoderm overlying the neural plate and regions of the involuting marginal zone (IMZ) not yet internalized during gastrulation remain E-cadherin-negative .
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Unlike most other species, Xenopus endodermal cells express no or very low levels of E-cadherin up to stage 20 NF (Nieuwkoop and Faber) .
These expression patterns highlight the specific role of E-cadherin in organizing epithelial tissues during Xenopus development and provide important context for interpreting experimental results using recombinant Cadherin-1 proteins.
Molecular Regulation of Cadherin-1
Cadherin-1 function is tightly regulated through various post-translational mechanisms to ensure appropriate cell adhesion dynamics during development and tissue homeostasis. Research using recombinant Cadherin-1 has contributed to our understanding of these regulatory processes.
Degradation Pathways and Cell Cycle Regulation
Studies have revealed that Cadherin-1 (Cdh1) stability is regulated by the ubiquitin-proteasome system, with SCF (Skp1-Cullin-F-box) ubiquitin ligase complexes playing a central role. Specifically, Cullin 1-based E3 ligase complexes have been implicated in controlling Cdh1 degradation . Experimental evidence shows that:
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Inactivation of Cullin 1 significantly increases endogenous Cdh1 abundance, while inactivation of other Cullins does not notably affect Cdh1 expression .
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A specific interaction between Cdh1 and Cullin 1 has been detected, both in overexpression systems and at endogenous levels .
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The F-box protein β-TRCP is involved in Cdh1 recognition, with depletion of β-TRCP1 and β-TRCP2 leading to increased steady-state levels of Cdh1 and abolished degradation of Cdh1 in late G1-S phase .
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Polo-like kinase 1 (Plk1) phosphorylates Cdh1 at multiple sites, including Ser138 and Ser146, creating a phosphodegron that is recognized by β-TRCP, thereby facilitating Cdh1 ubiquitination .
Protein Interactions and Sequestration
Beyond degradation, Cdh1 activity is also regulated through protein-protein interactions and sequestration. Research has identified that:
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Cdh1 interacts with MAD2L2 (Mad2l2), which can sequester Cdh1 and prevent its premature association with the Anaphase-Promoting Complex/Cyclosome (APC/C) .
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Gel filtration analysis of cell extracts shows that Cdh1 exists in two distinct pools during the cell cycle: in nocodazole-arrested cells, Cdh1 is found in low molecular weight fractions with MAD2L2, while in G1 cells, the majority of Cdh1 is in higher molecular weight fractions with CDC27 (a component of the APC/C) .
These regulatory mechanisms ensure proper timing of Cdh1 activity during the cell cycle and development, highlighting the importance of tight control over Cdh1 function.
Applications of Recombinant Xenopus laevis Cadherin-1
Recombinant Xenopus laevis Cadherin-1 serves as a valuable tool for various research applications, particularly in developmental biology, cell adhesion studies, and comparative analyses of cadherin function across species.
Immunological Applications
Recombinant Xenopus laevis Cadherin-1 serves as an important tool for developing and validating immunological reagents:
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The protein can be used as an antigen to generate specific antibodies for developmental studies and protein localization experiments.
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ELISA systems utilizing recombinant Cadherin-1 enable quantitative detection of the protein in various samples and experimental conditions .
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Antibodies generated against specific epitopes of recombinant Cadherin-1 have been instrumental in defining the temporal and spatial expression patterns during Xenopus development .
Functional Analyses in Development
Recombinant Cadherin-1 provides crucial insights into developmental processes:
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Function-blocking experiments using antibodies against recombinant Cadherin-1 enable assessment of its role in epithelial tissue formation and maintenance.
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Comparative studies utilizing recombinant Cadherin-1 from Xenopus and other species highlight evolutionary conservation and divergence in cadherin function.
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The characterization of Cadherin-1 in Xenopus has revealed unique features of its expression and function compared to mammalian and avian models, contributing to our understanding of the diverse roles of cadherins in vertebrate development .
Technical Considerations for Handling Recombinant Cadherin-1
Proper handling and storage of recombinant Xenopus laevis Cadherin-1 are essential for maintaining its biological activity and ensuring reliable experimental results.
Reconstitution Guidelines
Proper reconstitution is crucial for optimal protein activity:
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Lyophilized protein should be briefly centrifuged before opening to bring contents to the bottom of the vial .
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Reconstitution is typically performed in deionized sterile water to a concentration of 0.1-1.0 mg/mL .
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The addition of glycerol (5-50% final concentration) is recommended for aliquoting and long-term storage, with 50% being a common default concentration .
Product Specs
Note: We will prioritize shipping the format currently in stock. However, if you have specific format requirements, please specify them in your order. We will prepare according to your request.
Note: All our proteins are shipped with standard blue ice packs. If you require dry ice shipment, please inform us in advance. Additional fees will apply.
Generally, liquid form has a shelf life of 6 months at -20°C/-80°C. The shelf life of lyophilized form is 12 months at -20°C/-80°C.
Target Background
- JNK deficient embryos also exhibit increased intercellular adhesion and defects in e-cadherin localization. Conversely, embryos with overactive JNK show epidermal fragility, increased E-cadherin internalization, and increased membrane localized clathrin. PMID: 28032936
KEGG: xla:100337618
UniGene: Xl.7483
Q&A
What is Xenopus laevis Cadherin-1 and what are its common alternative names?
Cadherin-1 (cdh1) in Xenopus laevis is also known as Epithelial cadherin (E-cadherin), Uvomorulin, and xTCAD-1. It belongs to the classical cadherin family of calcium-dependent cell adhesion molecules. As a type I cadherin, it plays critical roles in maintaining epithelial tissue integrity and mediating morphogenetic processes during embryonic development . The protein has been well-characterized in various experimental systems including mammalian cell culture and Xenopus embryonic studies.
What is the molecular structure of Cadherin-1 in Xenopus laevis?
Xenopus laevis Cadherin-1 consists of five extracellular cadherin domains (EC1-EC5), a transmembrane region, and a cytoplasmic domain. The crystal structure of the complete ectodomain (EC1-EC5) from C-cadherin, a type I classical cadherin from Xenopus laevis, represents the only complete cadherin ectodomain structure published to date . This structure reveals a "strand swap" trans interface in which the N-terminal β-strand from the EC1 domain of each paired cadherin exchanges with that of the partner molecule . A second functionally important trans interface involving the linker region between EC1 and EC2 domains has also been identified and constitutes a kinetic intermediate in the formation of strand-swapped dimers .
How is Cadherin-1 expressed during Xenopus laevis development?
Cadherin-1 in Xenopus laevis shows a dynamic expression pattern during development. Both mRNA and protein products are present in unfertilized eggs, indicating maternal contribution . Immunolabeling studies using antibodies raised against bacterial fusion proteins containing EP-cadherin sequences have identified the protein in unfertilized eggs . Western blot analysis using pan-cadherin antibodies (R-156) recognizes a 125 x 10³ Mr polypeptide in Xenopus egg extracts . During early embryogenesis, molecules antigenically related to E-cadherin have been identified in cultured epithelial cell lines and in gastrulating embryos, suggesting important roles during these developmental stages .
How does the cis interface of Cadherin-1 contribute to its adhesive function?
The cis interface refers to lateral interactions between cadherin molecules on the same cell surface. Analysis of sequence conservation indicates that residues in the cis interface, like those of the known trans interfaces, are significantly more conserved than other surface residues, providing independent data suggesting a biological role for the cis interface . Specifically, cis interface residues in EC1-2 show 23% identity (7/31 residues) between E-, N-, P-, M- and R-cadherins (mouse and human) and C-cadherin (frog), compared with only 9% identity (6/66 residues) for non-interface surface residues . The observation of similar cis interfaces for three type I classical cadherins in unrelated crystal lattices further suggests potential biological relevance of these interactions .
What is the relationship between Cadherin-1 and β-catenin signaling?
E-cadherin functions as a tumor suppressor protein with a well-established role in cell-cell adhesion. Beyond its adhesive function, E-cadherin suppresses cellular transformation by inhibiting β-catenin signaling . When E-cadherin is expressed, it sequesters β-catenin at the cell membrane, preventing its nuclear translocation and transcriptional activity with LEF/TCF factors . Experimental evidence from transfection studies shows that colony formation (reflecting the anchorage-independent and dependent growth properties) is suppressed in cells expressing E-cadherin . This suppression can be overcome by co-expression of LEF/TCF factors, supporting the model that E-cadherin's tumor suppressor function is mediated in part through inhibition of β-catenin signaling .
How do cadherins contribute to tissue patterning during limb development in Xenopus?
Gene expression analysis of stage 51 Xenopus laevis hindlimb buds reveals differential expression of genes associated with cell adhesion across the proximodistal axis . Transcriptome analysis identified seven patterns of differential expression, with the distal region being most transcriptionally distinct . Genes linked to cell adhesion, along with signaling pathways including Wnt, Fgf, and retinoic acid (RA), show differential expression across the proximodistal axis . This pattern of expression supports the presence of morphogen gradients during early limb proximodistal axis patterning in Xenopus . While the specific role of Cadherin-1 in this process requires further investigation, these findings suggest that differential cell adhesion, potentially mediated by cadherins, contributes to the establishment of tissue boundaries and cellular behaviors during limb development.
What are optimal reconstitution and storage conditions for recombinant Xenopus laevis Cadherin-1?
The following table summarizes optimal storage and reconstitution conditions for recombinant Xenopus laevis Cadherin-1:
| Parameter | Recommendation |
|---|---|
| Storage temperature | -20°C/-80°C |
| Shelf life (liquid form) | 6 months |
| Shelf life (lyophilized form) | 12 months |
| Reconstitution | Deionized sterile water to 0.1-1.0 mg/mL |
| Additives | 5-50% glycerol (typically 50%) |
| Short-term storage | 4°C for up to one week |
| Handling notes | Avoid repeated freeze-thaw cycles; Briefly centrifuge vial before opening |
For experimental use, it's essential to follow these guidelines to maintain protein stability and activity . The addition of glycerol aids in preventing protein aggregation during freeze-thaw cycles, while maintaining proper temperature conditions is critical for preserving structural integrity.
What methods are used to detect and quantify Cadherin-1 expression in Xenopus tissues?
Several methods can be employed to detect and quantify Cadherin-1 expression in Xenopus tissues:
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Western Blotting: Protein extracts from tissues or cells are separated by SDS-PAGE and transferred to membranes. Cadherin-1 can be detected using specific antibodies such as anti-E-cadherin monoclonal antibody (HECD-1), anti-N-cadherin monoclonal antibody (3B9), pan-cadherin polyclonal antibody (R-156), or anti-β-catenin rabbit polyclonal antibody . HRP-conjugated secondary antibodies allow visualization with ECL systems .
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Immunofluorescence: For detecting nuclear β-catenin (related to cadherin function), cells can be fixed with methanol and processed according to standard immunofluorescence protocols . For detecting cadherins directly, rhodamine-labeled secondary antibodies can be used following primary antibody incubation .
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Immunohistochemistry: Albino Xenopus eggs can be stained using antibodies such as R-827 or R-156 and goat anti-rabbit antibodies conjugated to peroxidase. Following enzymatic reaction, eggs can be dehydrated, embedded in JB4 resin, sectioned (2-3 μm), and examined by microscopy .
How can stable cell lines expressing Cadherin-1 be established for functional studies?
Establishing stable cell lines expressing Cadherin-1 involves the following steps:
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Cell Selection: The SW480 human colon carcinoma cell line or CHO cells are commonly used for cadherin expression studies .
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Transfection: Cells can be transfected using Lipofectamine reagent with expression vectors containing the cadherin construct and a selection marker (e.g., pcDNA3neo or E-cadherin pcDNA3-neo for neomycin resistance) .
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Selection: Transfected cells are selected in media containing G418 (typically 800 μg/ml) for approximately 3 weeks .
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Clone Isolation: Stable clones can be initially isolated with cloning cylinders, expanded, and screened for protein expression by Western analysis .
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Subcloning: Positive clones should undergo one round of subcloning by limiting dilution and examination by immunofluorescence to ensure homogeneous clonal expression .
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Validation: Expression of Cadherin-1 can be confirmed by Western blotting using specific antibodies (e.g., anti-E-cadherin mAb HECD-1) .
For colony formation assays to test growth properties, 500 cells from each stable cell line can be seeded onto 10-cm dishes in appropriate media (e.g., DME supplemented with 10% FBS) .
How can sequence conservation analysis be used to identify functional domains in Cadherin-1?
Sequence conservation analysis is a powerful approach for identifying functionally important domains in Cadherin-1:
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Interface Residue Identification: Analysis of conserved residues can reveal important functional interfaces. For example, cis interface residues in EC1-2 show 23% identity between E-, N-, P-, M- and R-cadherins (mouse and human) and C-cadherin (frog), compared with only 9% identity for non-interface surface residues .
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Methodology:
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Align Cadherin-1 sequences from multiple species using tools like CLUSTAL
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Calculate conservation scores for each residue
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Map conservation onto structural models using tools like ConSurf
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Compare conservation patterns between interface and non-interface regions
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Interpretation: Higher conservation in specific regions suggests functional importance. For example, the significantly higher conservation of cis interface residues compared to other surface residues provides strong evidence for the biological relevance of the cis interface in cadherin function .
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Functional Validation: Conserved residues identified through sequence analysis can be targeted for mutagenesis studies to experimentally validate their functional importance in adhesion assays.
What are common technical challenges in Cadherin-1 research and how can they be addressed?
Several technical challenges may arise in Cadherin-1 research:
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Protein Stability Issues:
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Aggregation During Storage:
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Antibody Cross-Reactivity:
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Challenge: Antibodies may cross-react with other cadherin family members
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Solution: Use well-characterized antibodies specific for Cadherin-1; include appropriate negative controls
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Expression Level Variability:
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Functional Redundancy:
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Challenge: Other cadherins may compensate for Cadherin-1 function
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Solution: Use systems with minimal endogenous cadherin expression; consider combinatorial approaches to target multiple cadherins
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How can researchers distinguish between the specific functions of different cadherin subtypes in Xenopus?
Distinguishing between functions of different cadherin subtypes requires careful experimental design:
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Temporal Expression Analysis: Different cadherins show distinct temporal expression patterns during development. For example, E-cadherin is present in unfertilized eggs, while N-cadherin is first expressed at the neurula stage . Analyzing expression timing can help attribute developmental events to specific cadherins.
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Spatial Expression Analysis: In situ hybridization or immunohistochemistry can reveal tissue-specific expression patterns. For example, Xenopus E-cadherin and N-cadherin show distinct tissue distributions, with E-cadherin primarily in epithelial tissues and N-cadherin in neural tissues .
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Specific Antibodies: Using highly specific antibodies for different cadherin subtypes allows their distinct localization patterns to be determined. Pan-cadherin antibodies (R-156) recognize all cadherin subtypes, while other antibodies may be specific for particular cadherins .
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Gene Manipulation Approaches:
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Morpholino oligonucleotides for targeted knockdown
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CRISPR/Cas9 for genetic knockout
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Dominant-negative constructs (e.g., extracellular domain deletions)
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Cadherin subtype-specific rescue experiments
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Chimeric Proteins: Creating chimeric proteins with domains from different cadherins can help identify which domains confer subtype-specific functions.
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Isolation of Specific Effects: Using cell systems that lack endogenous cadherins (e.g., L cells) allows introduction of individual cadherin subtypes to assess their specific functional properties without interference from other family members.
What are emerging techniques that could advance our understanding of Cadherin-1 function?
Several cutting-edge techniques show promise for advancing Cadherin-1 research:
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Cryo-Electron Microscopy: While the crystal structure of C-cadherin ectodomain from Xenopus exists , cryo-EM could provide insights into larger cadherin assemblies and their interactions with cytoskeletal components.
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Super-Resolution Microscopy: Techniques like STORM, PALM, and STED microscopy can reveal nanoscale organization of cadherin clusters at cell-cell junctions with unprecedented detail.
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Optogenetics: Light-controlled manipulation of cadherin clustering or signaling could enable precise spatial and temporal control over adhesion strength and downstream signaling.
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CRISPR/Cas9 Genome Editing: Generation of cadherin knockout or knock-in Xenopus lines would facilitate in vivo studies of cadherin function during development.
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Single-Cell Transcriptomics: Analysis of cell-specific expression patterns in developing Xenopus embryos could reveal new insights into the coordination of different cadherin subtypes during morphogenesis.
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Biomechanical Measurements: Atomic force microscopy and optical tweezers can provide quantitative measurements of cadherin-mediated adhesion forces at the single-molecule level.
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Organoid Systems: Three-dimensional organoid cultures derived from Xenopus tissues could provide more physiologically relevant models for studying cadherin function in tissue organization.
How might understanding Cadherin-1 function in Xenopus contribute to broader developmental biology questions?
Research on Cadherin-1 in Xenopus has significant implications for fundamental questions in developmental biology:
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Morphogenetic Movements: Cadherin-mediated adhesion plays essential roles in coordinating cell movements during gastrulation, neurulation, and organogenesis. Understanding how Cadherin-1 function is regulated during these processes could reveal general principles of tissue morphogenesis .
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Cell Fate Decisions: Through its interaction with β-catenin, Cadherin-1 influences Wnt signaling, which is critical for cell fate decisions during development . Elucidating this regulatory interaction could provide insights into how adhesion and signaling are integrated during development.
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Evolutionary Conservation: Comparative studies of Cadherin-1 function across species can reveal evolutionarily conserved mechanisms of tissue organization. The high degree of sequence conservation in functional interfaces suggests fundamental roles that have been maintained throughout evolution .
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Tissue Boundary Formation: Differential cadherin expression contributes to the establishment of tissue boundaries. Analysis of cadherin expression during limb development in Xenopus reveals patterns that may contribute to proximodistal patterning .
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Scaling in Development: Xenopus embryos can develop normally across a range of sizes. Understanding how cadherin-based adhesion adapts to different tissue scales could provide insights into developmental scaling mechanisms.
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Regeneration Biology: Xenopus has significant regenerative capabilities. Investigating how cadherins function during regenerative processes could illuminate the role of cell adhesion in regeneration.
