Recombinant Nematostella vectensis Spastin (v1g144095)

What is Nematostella vectensis and why has it emerged as an important model organism?

Nematostella vectensis (starlet sea anemone) is a small estuarine sea anemone that has become a significant model organism in evolutionary developmental biology (EvoDevo). It belongs to Cnidaria, a sister group to Bilateria, making it valuable for understanding the evolution of key bilaterian features . This organism has a unique distribution across the Northwest Atlantic from Nova Scotia to Louisiana, Northeast Pacific from Washington to California, and limited locations in southeast England .

Nematostella vectensis gained prominence as a model system due to several distinct advantages:

• Its phylogenetic position makes it ideal for comparative studies with bilaterians

• It possesses remarkable regenerative capabilities

• Its genome has been sequenced and contains many genes conserved with bilaterians

• It is amenable to genetic manipulation techniques

The species has transitioned from an ecological curiosity to a powerful laboratory model for studying fundamental questions in developmental biology, regeneration, and evolution of complex body plans .

What expression systems are used for recombinant production of Nematostella vectensis Spastin?

Multiple expression systems have been employed to produce recombinant Nematostella vectensis Spastin, each with distinct advantages depending on research requirements:

The E. coli system appears to be preferred for producing the full-length protein with an N-terminal His tag , while mammalian expression systems have been used for partial length variants . The choice between these systems typically depends on:

• Required protein yield

• Downstream applications (structural studies, functional assays)

• Need for post-translational modifications

• Solubility considerations

The methodology for purification likely involves affinity chromatography utilizing the His-tag, followed by additional purification steps to achieve the reported >85-90% purity .

What are the optimal protocols for reconstitution and storage of Recombinant Nematostella vectensis Spastin?

Based on manufacturer recommendations and standard protein handling protocols, the following methodological approach is suggested for reconstitution and storage:

Reconstitution Protocol:

• Centrifuge the vial briefly before opening to bring contents to the bottom

• Reconstitute lyophilized protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL

• Add glycerol to a final concentration of 5-50% (50% is the standard recommendation)

• Aliquot for long-term storage to prevent repeated freeze-thaw cycles

Storage Conditions and Stability:

The reconstitution buffer typically consists of Tris/PBS-based buffer with 6% Trehalose, pH 8.0 . For working aliquots, storage at 4°C is recommended for up to one week to maintain protein activity while avoiding freeze-thaw cycles .

The shelf life of the protein is influenced by multiple factors including buffer composition, storage temperature, and the intrinsic stability of the protein itself . Researchers should validate protein activity for their specific applications after extended storage periods.

How can researchers verify the activity and structural integrity of recombinant Spastin?

To ensure experimental validity, researchers should employ multiple complementary approaches to verify both the structural integrity and functional activity of recombinant Spastin:

Structural Integrity Assessment:

• SDS-PAGE analysis to confirm molecular weight and purity (>85-90% as indicated in product specifications)

• Western blotting with anti-His antibodies or specific anti-Spastin antibodies

• Mass spectrometry for precise molecular weight determination and confirmation of sequence coverage

• Circular dichroism (CD) spectroscopy to evaluate secondary structure elements

• Dynamic light scattering (DLS) to assess homogeneity and detect potential aggregation

Functional Activity Verification:

• ATPase activity assay (as Spastin is classified as EC 3.6.4.3, indicating ATP hydrolysis function)

• Microtubule-severing assay using fluorescently labeled microtubules

• Binding assays to evaluate interaction with known Spastin partners

The specific assays should be tailored to the intended experimental applications. For structural studies, additional biophysical characterization may be necessary, while functional studies might require cell-based assays to evaluate physiological activity.

What is the relationship between Nematostella vectensis Spastin and segment polarity development?

Recent spatial transcriptomics research has revealed fundamental insights into segment polarity mechanisms in Nematostella vectensis, though Spastin's specific role in this process is not directly addressed in the provided search results .

Key findings from spatial transcriptomics studies include:

• Nematostella endomesodermal tissue forms metameric segments with transcriptomic profiles similar to bilaterian mesoderm

• A comprehensive 3D gene expression atlas has been constructed to systematically analyze segmental identity in endomesoderm

• Two conserved homeobox-containing genes, Lbx and Uncx, establish segment polarity in Nematostella

• These genes occupy opposing subsegmental domains under the control of both BMP signaling and the Hox-Gbx cascade

• Functional studies demonstrate that Lbx mutagenesis eliminates molecular evidence of segment polarization at the larval stage and causes aberrant mirror-symmetric patterns of retractor muscles in primary polyps

These findings suggest that polarized metameric structures likely existed in the Cnidaria-Bilateria common ancestor over 600 million years ago . While Spastin's specific role in this developmental context requires further investigation, it may participate in cytoskeletal remodeling processes that support segment formation, given its predicted microtubule-severing activity.

How does Nematostella vectensis Spastin compare structurally and functionally to its homologs in other species?

A comparative analysis of Spastin across species provides important evolutionary context:

While the search results don't provide direct comparative information, Spastin proteins generally show conserved functional domains across diverse organisms from invertebrates to humans. Based on the enzyme classification (EC 3.6.4.3) and sequence characteristics, Nematostella vectensis Spastin likely shares core functional properties with its homologs.

Typical conserved features in Spastin proteins include:

• MIT (Microtubule Interacting and Trafficking) domain for interaction with microtubules and adapter proteins

• AAA ATPase domain responsible for ATP hydrolysis and microtubule severing activity

• Potential regulatory regions that modulate activity in different cellular contexts

Phylogenetic analyses could reveal the evolutionary relationship between Nematostella vectensis Spastin and homologs in other organisms, potentially providing insights into the ancestral functions of this protein family. This evolutionary perspective is particularly valuable given Nematostella's position as a basal eumetazoan.

Research gaps still exist in understanding species-specific adaptations in Spastin structure-function relationships, particularly in non-model organisms such as Nematostella vectensis.

What experimental approaches can be used to study Spastin's role in Nematostella vectensis development and regeneration?

Given Nematostella's emerging role as a model for developmental and regenerative biology , several methodological approaches can be employed to investigate Spastin's functions:

Genetic Manipulation Techniques:

• CRISPR/Cas9 mutagenesis targeting the Spastin gene, similar to approaches used for Lbx

• Morpholino knockdown for transient functional inhibition

• Transgenic overexpression with tissue-specific promoters

Imaging and Expression Analysis:

• In situ hybridization to characterize spatial expression patterns during development and regeneration

• Immunohistochemistry with anti-Spastin antibodies

• Integration with the established 3D gene expression atlas from spatial transcriptomics studies

• Live imaging of fluorescently tagged Spastin to track dynamics during developmental processes

Functional Assays:

• Analysis of microtubule dynamics and organization in wild-type versus Spastin-mutant contexts

• Assessment of cell migration, division, and morphological changes during development and regeneration

• Phenotypic characterization of segment formation and polarization in Spastin mutants

• Investigation of potential interactions with segment polarity regulators like Lbx and Uncx

When designing these experiments, researchers should consider the environmental tolerance of Nematostella vectensis (salinity range: 2-52 PSU, temperature range: -1.5-32.5°C) , as these parameters may influence developmental and regenerative processes.

What are the key considerations for using Recombinant Nematostella vectensis Spastin in in vitro assays?

When designing in vitro experiments with recombinant Spastin, researchers should address several methodological considerations:

Buffer and Reaction Conditions:

• Optimal pH range: Typically between 7.0-8.0 for enzymatic activity based on storage buffer recommendations (pH 8.0)

• Salt concentration: Standard buffers for ATPase assays typically contain 150 mM NaCl, but optimization may be required

• Divalent cations: As an ATPase, Spastin likely requires Mg²⁺ (typically 1-5 mM)

• ATP concentration: Typically 1-2 mM for ATPase activity assays

• Reducing agents: Addition of DTT or β-mercaptoethanol (0.5-1 mM) to maintain protein stability

Experimental Controls:

• Heat-inactivated Spastin as a negative control

• Spastin with non-hydrolyzable ATP analogs (ATP-γ-S) to distinguish between binding and hydrolysis

• Known microtubule-severing proteins (e.g., katanin) as positive controls

• Concentration gradients to establish dose-dependency

Potential Interferences:

• Glycerol from storage buffer may affect some assays at high concentrations

• His-tag might influence activity or interactions in certain contexts

• Detergents or other buffer components may interfere with protein-protein or protein-substrate interactions