Recombinant Danio rerio Transmembrane protein 179 (tmem179)

What is the basic genetic structure of tmem179 in Danio rerio?

Transmembrane protein 179 (tmem179) in Danio rerio is a protein-coding gene with the Entrez Gene ID 100537383. The gene encodes a transmembrane protein that is expressed in zebrafish . Based on current annotation data, the gene produces multiple transcript variants, with XM_003200379.4 and XM_003200379.5 representing two documented sequences that encode the same protein product (XP_003200427.1) . The complete open reading frame (ORF) of the zebrafish tmem179 gene spans 702 base pairs, encoding a functional protein that belongs to the transmembrane protein family .

How is tmem179 evolutionarily conserved across species?

Tmem179 demonstrates significant evolutionary conservation across multiple vertebrate species. The protein sequence reveals homology with transmembrane protein 179 found in:

This cross-species conservation suggests fundamental biological importance, with zebrafish tmem179 sharing key structural and potentially functional domains with mammalian counterparts . The protein family extends to invertebrate species as well, with related proteins identified in Drosophila melanogaster (CG13603) and Anopheles gambiae (AgaP_AGAP004210), indicating ancient evolutionary origins .

What expression systems are recommended for recombinant production of Danio rerio tmem179?

For recombinant expression of zebrafish tmem179, mammalian expression systems are typically preferred due to the protein's transmembrane nature and potential requirement for post-translational modifications. The optimized methodology includes:

• Vector selection: pcDNA3.1-C-(k)DYK or equivalent mammalian expression vectors that provide appropriate promoters and selection markers

• Cell line optimization: HEK293 or CHO cells are recommended for transmembrane protein expression

• Transfection protocol: Lipid-based transfection reagents at 70-80% cell confluency

• Expression verification: Western blot analysis using appropriate antibodies, such as goat polyclonal antibodies raised against specific peptide epitopes

The clone ID ODa22866 corresponds to validated expression constructs containing the tmem179 ORF, which can be directly utilized for recombinant protein production in appropriate expression systems .

How does tmem179 function in relation to the antiviral immune response in zebrafish?

While specific information on tmem179's role in antiviral immunity is limited, research on the related transmembrane protein TMEM33 in zebrafish provides valuable insights into potential functional mechanisms. TMEM33 has been identified as a negative regulator of virus-triggered interferon (IFN) induction through two distinct mechanisms :

• Promotion of K48-linked ubiquitination of mitochondrial antiviral signaling protein (MAVS), leading to its degradation

• Decrease in the kinase activity of TANK binding kinase 1 (TBK1), which reduces phosphorylation of MITA/IRF3

Experimental evidence demonstrates that TMEM33 localizes to the endoplasmic reticulum and directly interacts with RIG-I-like receptor (RLR) signaling cascades. Upon viral stimulation, tmem33 gene expression is significantly upregulated in zebrafish liver cells, suggesting induction as part of the antiviral response regulatory network . Knockdown experiments show that reducing TMEM33 levels increases interferon transcription, further supporting its role as a negative regulator of the antiviral response .

What are the critical functional domains of tmem179 essential for protein-protein interactions in immune signaling?

Structure-function analysis of the related TMEM33 protein identifies crucial transmembrane domains that may share functional significance with tmem179. Domain mapping experiments reveal:

Functional domain assays demonstrate that the N-terminal TM1 and TM2 regions are necessary for interferon suppression activity . These domains likely facilitate protein-protein interactions with immune signaling components, including potential interactions with MAVS and TBK1. For tmem179, similar transmembrane topology may indicate comparable functional domains, though specific experimental confirmation for tmem179 remains necessary.

What methodological approaches are recommended for studying tmem179 subcellular localization and trafficking?

To investigate subcellular localization and trafficking of tmem179, the following methodological approach is recommended:

• Fluorescent protein tagging: Generate C-terminal or N-terminal GFP/RFP fusion constructs with tmem179 ORF, ensuring tag placement doesn't disrupt transmembrane domains

• Confocal microscopy: Perform live-cell imaging in zebrafish cell lines transfected with fluorescent-tagged tmem179

• Co-localization studies: Use established markers for cellular compartments (ER-Tracker, MitoTracker, etc.) to determine precise subcellular location

• FRAP (Fluorescence Recovery After Photobleaching): Assess protein mobility and trafficking dynamics within membrane systems

• Immunogold electron microscopy: For higher resolution localization using specific antibodies against tmem179

Based on studies of related proteins, tmem179 is likely localized to the endoplasmic reticulum, similar to TMEM33 which influences ER tubular structure and calcium homeostasis . Verification of tmem179's specific localization pattern is essential for understanding its functional significance in zebrafish cells.

What are the optimal conditions for expressing and purifying recombinant zebrafish tmem179 for structural studies?

For structural studies of recombinant zebrafish tmem179, a multi-step optimization protocol is recommended:

• Expression system selection:

  • Insect cell systems (Sf9, High Five) for higher yields of membrane proteins

  • Mammalian expression systems for native post-translational modifications

  • E. coli systems with specialized strains (C41, C43) for preliminary constructs

• Construct optimization:

  • Remove flexible regions identified by secondary structure prediction

  • Consider truncated constructs focusing on specific domains

  • Add purification tags (His6, FLAG) at termini less likely to interfere with folding

• Purification strategy:

  • Membrane extraction using mild detergents (DDM, LMNG, or GDN)

  • Two-step affinity chromatography followed by size exclusion

  • Detergent exchange during purification for stability optimization

• Stability screening:

  • Thermal shift assays to identify optimal buffer conditions

  • Limited proteolysis to identify stable domains

The validated clone ID ODa22866 can serve as the starting material for these optimization protocols, with expression verification performed using specific antibodies such as the affinity-purified goat polyclonal antibody raised against tmem179 peptide epitopes .

How can gene editing approaches be utilized to study tmem179 function in zebrafish models?

CRISPR-Cas9 gene editing provides a powerful approach for studying tmem179 function in zebrafish:

• Guide RNA design:

  • Target exonic regions with high specificity scores

  • Design multiple gRNAs targeting different exons to increase success rate

  • Verify lack of off-target effects using bioinformatic prediction tools

• Delivery method:

  • Microinjection of Cas9 protein with synthesized gRNAs into one-cell stage embryos

  • Alternative: injection of Cas9 mRNA with gRNAs for longer expression

• Mutation verification:

  • High-resolution melting analysis (HRMA) for rapid screening

  • T7 endonuclease I assay for detecting indels

  • Targeted sequencing to confirm exact mutations

• Phenotypic analysis:

  • Assess development and morphology during embryogenesis

  • Examine immune response to viral challenges by measuring interferon levels

  • Evaluate calcium homeostasis and ER morphology using fluorescent indicators

• Rescue experiments:

  • Reintroduce wild-type or mutant tmem179 to validate phenotype specificity

  • Use tissue-specific promoters to address cell-autonomous effects

Given the potential role of tmem179 in immune regulation, as suggested by studies on TMEM33 , particular attention should be paid to immunological parameters and response to pathogen challenges in the gene-edited models.

What approaches are recommended for studying protein-protein interactions between tmem179 and potential binding partners?

To investigate protein-protein interactions involving tmem179, a multi-faceted approach is recommended:

• Co-immunoprecipitation (Co-IP):

  • Express epitope-tagged tmem179 in zebrafish cells

  • Perform IP with tag-specific antibodies followed by mass spectrometry

  • Validate interactions with specific antibodies against predicted partners

• Proximity labeling techniques:

  • Generate BioID or TurboID fusion constructs with tmem179

  • Express in zebrafish cells and identify proximal proteins through biotin labeling

  • This approach is particularly valuable for transmembrane proteins with transient interactions

• FRET/BRET analysis:

  • Create fluorescent protein pairs with tmem179 and candidate interactors

  • Measure energy transfer as evidence of close molecular proximity

  • Particularly useful for confirming direct interactions in living cells

• Split-reporter assays:

  • Utilize split-GFP or NanoBiT complementation systems

  • Generate fusion constructs with tmem179 and potential partners

  • Monitor reporter activation as evidence of interaction

Based on findings from related proteins, potential interacting partners to investigate include components of the RIG-I-like receptor signaling pathway, MAVS, TBK1, and ER structural proteins . The N-terminal transmembrane domains (TM1 and TM2) should be specifically examined for their role in mediating these interactions.

How can researchers reconcile contradictory findings regarding tmem179 function across different model systems?

When facing contradictory results regarding tmem179 function, implement this systematic approach:

• Model system differences assessment:

  • Compare protein sequence homology across species using multiple sequence alignment

  • Evaluate expression patterns in different tissues/developmental stages

  • Consider differences in signaling pathway components between models

• Experimental methodology evaluation:

  • Scrutinize knockout/knockdown efficiency and specificity

  • Compare protein tagging strategies that might affect function

  • Analyze differences in experimental conditions (temperature, pH, ionic strength)

• Resolution strategies:

  • Perform parallel experiments in multiple systems under identical conditions

  • Use complementary approaches (genetic knockdown, chemical inhibition)

  • Develop domain swap experiments to identify species-specific functional regions

• Data integration framework:

  • Generate a comprehensive model that accounts for apparent contradictions

  • Consider context-dependent functions that might explain different observations

  • Use quantitative approaches to determine relative contributions of different pathways

When studying zebrafish tmem179, particular attention should be paid to developmental timing and tissue-specific effects, as zebrafish embryonic development involves distinct maternal and zygotic gene expression programs .

What are the critical considerations when developing antibodies against zebrafish tmem179?

Developing effective antibodies against zebrafish tmem179 requires careful planning:

• Epitope selection strategy:

  • Target extracellular or cytoplasmic domains rather than transmembrane regions

  • Use species-specific sequences to avoid cross-reactivity

  • Select regions with high antigenicity and surface probability

  • Consider multiple epitopes to increase success probability

• Immunization considerations:

  • Use synthetic peptides conjugated to carrier proteins

  • Consider recombinant protein fragments expressed in E. coli

  • Immunize species phylogenetically distant from zebrafish

• Validation requirements:

  • Western blot against recombinant protein and zebrafish tissue extracts

  • Immunoprecipitation efficiency testing

  • Immunofluorescence to confirm expected subcellular localization

  • Comparison between wildtype and tmem179-depleted samples

• Cross-reactivity testing:

  • Evaluate against related proteins (TMEM33, other TMEM family members)

  • Test in multiple zebrafish tissues to confirm specificity

Commercial antibodies, such as the affinity-purified goat polyclonal antibody raised against a tmem179 peptide epitope, can serve as reference standards . These antibodies are typically validated for research applications but should be independently verified for specific experimental conditions.

What analytical approaches are recommended for investigating the impact of tmem179 on cellular calcium homeostasis?

To investigate tmem179's potential role in calcium homeostasis, similar to TMEM33 , implement this methodological framework:

• Real-time calcium imaging:

  • Utilize ratiometric indicators (Fura-2) or genetically encoded sensors (GCaMP)

  • Monitor baseline calcium levels in wildtype vs. tmem179-deficient cells

  • Measure calcium flux dynamics following store depletion (thapsigargin treatment)

  • Assess response to physiological stimuli that mobilize calcium

• ER calcium store measurement:

  • Use specific ER-targeted calcium indicators

  • Quantify ER calcium content through controlled release experiments

  • Analyze refilling kinetics following store depletion

• Electrophysiological approaches:

  • Patch-clamp analysis of calcium currents

  • Characterize store-operated calcium entry (SOCE)

  • Measure channel open probability in the presence/absence of tmem179

• Protein-protein interaction analysis:

  • Investigate associations with known calcium handling proteins (STIM, Orai)

  • Examine co-localization with ER-plasma membrane contact sites

  • Assess phosphorylation status under calcium flux conditions

• Data integration:

  • Develop mathematical models of calcium dynamics

  • Perform sensitivity analysis to quantify tmem179's contribution

  • Compare with effects of known calcium regulators

This comprehensive approach will help distinguish direct effects of tmem179 on calcium homeostasis from indirect consequences, providing insight into its fundamental cellular function.

How can zebrafish tmem179 research contribute to understanding human disease mechanisms?

Zebrafish tmem179 research offers valuable insights into human disease mechanisms through several translational pathways:

• Comparative genomics approach:

  • The human TMEM179 gene maps to chromosome 14, which contains approximately 700 genes and is associated with several genetic disorders

  • Functional conservation between zebrafish and human proteins allows modeling of human disease variants

  • Specific domains critical for function in zebrafish can guide analysis of human mutations

• Immune regulation insights:

  • Given the role of related proteins in antiviral immunity , tmem179 research may inform understanding of immunodeficiency disorders

  • Mechanisms of interferon regulation identified in zebrafish could reveal novel therapeutic targets for autoimmune conditions

  • Viral challenge models in zebrafish can recapitulate aspects of human viral susceptibility

• Developmental disease modeling:

  • Zebrafish embryonic development provides a visible, accessible system to study genes with developmental roles

  • High-throughput screening capabilities allow testing of genetic and chemical modifiers

  • Cellular processes affected by tmem179 dysfunction can be linked to human pathologies

• Therapeutic target validation:

  • Genetic rescue experiments in zebrafish can validate mechanism-based therapeutic approaches

  • Small molecule screens can identify compounds that modulate tmem179 function

  • Humanized zebrafish models expressing human TMEM179 variants can evaluate personalized interventions

The established role of chromosome 14 genes in human disorders like Alzheimer's disease (through presenilin 1) and α1-antitrypsin deficiency highlights the potential significance of all genes in this region, including TMEM179, in human health .

What methodological considerations are important when correlating zebrafish tmem179 findings with human TMEM179 function?

When translating findings from zebrafish tmem179 to human TMEM179, the following methodological approaches are essential:

• Sequence and structure comparison:

  • Perform detailed alignment of protein sequences to identify conserved domains

  • Use homology modeling to predict structural similarities and differences

  • Identify post-translational modification sites that may differ between species

• Expression pattern analysis:

  • Compare tissue-specific expression profiles between zebrafish and human tissues

  • Analyze temporal expression patterns during development

  • Identify cell types expressing TMEM179 in both species

• Functional complementation studies:

  • Express human TMEM179 in zebrafish tmem179 mutants to assess functional rescue

  • Create chimeric proteins with domain swaps to identify species-specific regions

  • Use CRISPR/Cas9 to humanize zebrafish tmem179 sequences

• Disease-relevant phenotyping:

  • Develop assays in zebrafish that reflect human pathological processes

  • Assess both molecular and physiological parameters with clinical relevance

  • Incorporate environmental factors that influence disease manifestation

• Data validation in human systems:

  • Confirm key findings in human cell lines or patient-derived samples

  • Utilize tissue-specific differentiated cells from human iPSCs

  • Correlate zebrafish phenotypes with human clinical data when available

This systematic approach ensures that insights gained from the experimentally accessible zebrafish model can be meaningfully translated to human biology and pathology.