KRT18 Bovine
Description
Definition and Basic Properties
KRT18 Bovine refers to the type I intermediate filament protein Keratin-18 derived from Bos taurus (cattle). It is structurally homologous to human KRT18 but exhibits species-specific functional nuances . Key characteristics include:
| Property | Specification |
|---|---|
| Molecular Mass | 45 kDa (calculated) |
| Isoelectric Point (pI) | 5.4 |
| Source | Bovine liver |
| Physical Form | Lyophilized powder, sterile-filtered |
| Stability | Store lyophilized at 2–8°C; reconstituted at -20°C (avoid freeze-thaw cycles) |
| Purity | >95% (SDS-PAGE verified) |
This protein is commercially available under catalog numbers such as PRO-2785 (Prospec Bio) and ABIN935141 (Antibodies-Online) .
Regulatory Roles
KRT18 modulates gene expression and alternative splicing (AS) of apoptosis-related pathways, as observed in gastric cancer studies (though primarily in human models) . Bovine-specific research remains limited but suggests conserved regulatory mechanisms .
Veterinary and Agricultural Relevance
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Cattle Production: KRT18 mutations may impact meat quality and disease resistance, offering targets for selective breeding .
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Disease Modeling: Bovine KRT18-expressing cells are used to study epithelial diseases like Johne’s disease (Mycobacterium avium infection) in intestinal organoids .
Comparative Studies
Key Findings from 2022–2025:
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Embryo Development: KRT18 knockdown reduces KRT8 expression, impairing bovine embryo viability .
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Organoid Models: Bovine intestinal organoids show upregulated KRT18 transcripts, suggesting roles in mucosal immunity .
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Biotechnological Tools: Recombinant KRT18 is used to study epithelial resilience under metabolic stress .
Reconstitution Guidelines
Challenges and Future Directions
While bovine KRT18 research lags behind human studies, its unique applications in agriculture and translational medicine are gaining traction. Priority areas include:
Product Specs
Keratin type I cytoskeletal 18, Cytokeratin-18, CK-18, Keratin-18, K18, KRT18,CYK18,Cell proliferation-inducing gene 46 protein.
Bovine liver.
Q&A
What experimental approaches are used to determine the spatiotemporal expression of KRT18 in bovine preimplantation embryos?
To map KRT18 expression, researchers employ immunofluorescence microscopy with stage-specific embryo collection (e.g., zygote to blastocyst stages) . Trophectoderm-specific localization is validated using:
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Phalloidin co-staining to correlate with F-actin architecture
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RNA in situ hybridization to distinguish trophoblast vs. inner cell mass expression
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qRT-PCR on microdissected embryonic tissues to quantify mRNA dynamics
Key finding: KRT18 expression initiates at blastocyst formation (Day 7–8 in bovines) and is restricted to trophectoderm cells, making it a lineage-specific marker .
How does KRT18 knockdown affect bovine blastocyst formation and quality?
Standard protocols involve RNA interference (RNAi) via cytoplasmic microinjection of double-stranded KRT18 RNA into zygotes :
| Parameter | Control Blastocysts | KRT18-KD Blastocysts |
|---|---|---|
| Blastocyst formation rate | 45.2% ± 3.1 | 26.7% ± 2.8* |
| KRT18 mRNA reduction | - | 76% ± 5.3* |
| Trophectoderm integrity | Intact | Disorganized F-actin |
Mechanistically, KRT18 knockdown disrupts trophectoderm cell-cell adhesion by reducing E-cadherin membrane stabilization (KD reduces E-cadherin expression by 58% in bovine trophoblasts) .
What functional assays are used to study KRT18’s role in embryo implantation?
Three primary models are utilized:
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In vitro embryo adhesion assays: Co-culture blastocysts with endometrial epithelial monolayers (e.g., Ishikawa cells) under shear stress to quantify attachment rates .
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Ex vivo implantation models: Transfer siRNA-treated embryos into pseudopregnant mice/uteri to count implantation sites .
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Trophoblast spheroid-endometrial attachment assays: Measure JEG-3 spheroid adhesion to endometrial cells post-KRT18 knockdown .
How does KRT18 regulate alternative splicing in bovine trophoblast differentiation?
Emerging evidence suggests KRT18 modulates splicing via RNA-binding protein interactions. In bovine trophoblasts, KRT18 knockdown alters splicing patterns of:
Methodological validation involves:
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Whole-transcriptome RNA-seq with rMATS for splicing quantification
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CLIP-seq to identify KRT18-associated spliceosome components
What molecular techniques confirm direct KRT18-E-cadherin interactions in bovine embryos?
Two complementary approaches are critical:
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Microscale thermophoresis (MST): Quantifies binding affinity (reported Kd = 5.6 μM for bovine KRT18-E-cadherin) .
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Proximity ligation assays (PLA): Visualizes in situ interactions using anti-KRT18 and anti-E-cadherin probes .
Contradiction alert: While bovine studies show strong KRT18-E-cadherin colocalization , murine models report partial compensation by KRT8 . Species-specific validation is essential.
How do researchers reconcile conflicting data on KRT18’s role across experimental models?
Key discrepancies and resolution strategies:
| Discrepancy | Resolution Approach |
|---|---|
| 41% vs. 23% blastocyst formation loss | Standardize RNAi efficiency metrics |
| Variable E-cadherin downregulation | Use tandem KD (KRT18 + KRT8) models |
| Species-specific compensatory effects | Cross-species CRISPR knockout screens |
How to address off-target effects in bovine KRT18 knockdown studies?
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Multiplex siRNA validation: Compare ≥3 siRNA sequences targeting different KRT18 exons
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Rescue experiments: Co-transfect siRNA with codon-optimized KRT18 cDNA (bovine-specific variants)
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Single-cell RNA-seq: Profile individual embryo cells post-KD to identify aberrant pathways
What systems biology approaches elucidate KRT18’s interactome?
Integrative multi-omics pipelines:
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Proximity-dependent biotinylation (BioID): Identify KRT18-associated proteins in bovine trophoblasts
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Weighted gene co-expression networks (WGCNA): Link KRT18 expression clusters to implantation competence
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Machine learning models: Predict blastocyst viability from KRT18/E-cadherin co-expression patterns
Future Directions
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Develop bovine trophoblast organoids with inducible KRT18 mutations to study implantation mechanics.
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Explore KRT18 phosphorylation mutants (e.g., Ser33/52) using CRISPR-Cas9 base editing.
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Establish single-molecule tracking to visualize KRT18-E-cadherin dynamics in living embryos.
Product Science Overview
CK18 is a specific marker for bovine intestinal M cells, which are specialized epithelial cells found in the follicle-associated epithelium (FAE) of Peyer’s patches . These cells play a significant role in mucosal immune responses by transporting antigens from the lumen to immune cells. The expression of CK18 in these cells helps in identifying and studying their function and behavior.
In bovine intestinal cells, CK18 is expressed in the jejunal and ileal FAE regions. The expression patterns of CK18 are similar to the localization of M cells, which have irregular and sparse microvilli and pocket-like structures containing lymphocytes . This specific expression pattern makes CK18 a valuable marker for identifying M cells in bovine studies.
CK18-positive cells in the bovine intestine exhibit typical morphological characteristics of M cells, such as irregular microvilli and the presence of lymphocytes in pocket-like structures. In contrast, CK18-negative cells have regular and dense microvilli, typical of enterocytes .
Research on CK18 in bovine species has provided insights into the differentiation and function of intestinal epithelial cells. For example, studies have shown that CK18-positive M cells in the crypt continue to express CK18 as they move to the FAE region, while CK18-negative cells transition to CK20-positive enterocytes and undergo apoptosis at the apex of the FAE .
The specific expression of CK18 in bovine M cells has also been used to study the interactions between intestinal epithelial cells and pathogens, as well as the immune responses in the gut. This research has implications for understanding bovine health and developing strategies to improve immune responses in livestock.
