Recombinant Mouse Uncharacterized protein KIAA1107 (Kiaa1107), partial

What are the general characteristics of KIAA1107 protein?

KIAA1107 is a serine-rich protein that has been linked to increased expression in white matter of Multiple Sclerosis brain lesions. In humans, the full-length protein (isoform A) consists of 1401 amino acids with a predicted molecular weight of 149.6 kDa. The protein contains a higher frequency of Serine (14.0%) and Aspartate (7.5%) compared to average human proteins, qualifying it as a Serine-rich protein. It also has notably lower Tyrosine content (0.7%) than typical human proteins .

While specific data on mouse KIAA1107 is limited in the provided search results, we can draw some understanding from human KIAA1107 characteristics and other KIAA family proteins in mice. The protein contains a conserved domain, DUF4596 (Domain of Unknown Function), located at positions 1311-1354 in the human variant, though the function of this domain remains undetermined .

What is known about KIAA1107 gene structure and variants?

The human KIAA1107 gene is located on chromosome 1 at cytogenetic band 1p22.1, spanning positions 92,067,052 bp - 92,184,723 bp from pter, with a total of 17,672 bases. The gene contains nine known exons that can undergo alternative splicing to produce multiple transcript variants .

Transcription of human KIAA1107 produces 6 different mRNAs, including 4 alternatively spliced variants and 2 unspliced forms. The variants include:

• Variant A (most common): Contains all nine exons (1-9) in standard form

• Variant B: Contains seven exons (3-9) in standard form

• Variant C-U: Contains one alternatively spliced variant of exon 8

• Variant D: Contains five exons (1-4, 5a) with an alternative form of exon 5

• Variant E: Contains three alternatively spliced forms of exons 3, 4, and 5

• Variant F-U: Contains one alternatively spliced form of exon 5a

Mouse models would likely share some structural similarities, though specific information on mouse KIAA1107 gene structure is not explicitly detailed in the search results.

What are the expression patterns of KIAA1107 in different tissues?

KIAA1107 expression is not ubiquitous across tissues. In humans, it is predominantly expressed in brain tissue, with lower expression levels detected in bladder, mammary gland, muscle, prostate, and testis. Within the brain, highest expression is observed in the pineal gland, prefrontal cortex, cingulate cortex, and subthalamic nucleus .

This expression pattern suggests potential neurological functions, which is further supported by its reported overexpression in white matter of Multiple Sclerosis brain lesions . For mouse models, expression patterns may differ, but based on other KIAA family proteins like mKiaa1211, there may be developmental regulation of expression in neural tissues .

How should researchers approach the initial characterization of recombinant mouse KIAA1107?

For initial characterization of recombinant mouse KIAA1107, researchers should consider:

• Protein verification: Confirm protein identity and purity using SDS-PAGE, western blotting, and mass spectrometry

• Structure analysis: Conduct circular dichroism (CD) spectroscopy to analyze secondary structure elements

• Expression profiling: Perform qPCR analysis across different tissues and developmental stages to establish spatiotemporal expression patterns, similar to approaches used for other KIAA family proteins

• Domain mapping: Verify the presence and location of conserved domains, particularly focusing on the DUF4596 domain identified in human KIAA1107

Based on approaches used with related proteins, researchers might consider using whole-mount in situ hybridization to visualize expression patterns during developmental stages, as was done for mKiaa1211 in mouse embryonic development .

What experimental design considerations are critical when studying recombinant mouse KIAA1107?

When designing experiments involving recombinant mouse KIAA1107, researchers should:

• Clearly define variables: Establish independent variables (e.g., KIAA1107 expression levels, mutations, or tissue-specific knockout) and dependent variables (e.g., phenotypic changes, molecular pathway alterations)

• Control for confounding factors: Since KIAA1107 is predominantly expressed in brain tissue with specific expression patterns, tissue-specific controls are essential. Consider using:

  • Age-matched and sex-matched controls

  • Tissue-specific expression models

  • Conditional knockout systems for temporal control

• Validate recombinant protein quality: Before experimental use, verify:

  • Proper folding using structural analysis techniques

  • Biological activity through functional assays

  • Absence of carrier proteins that might interfere with results

• Design appropriate reconstitution protocols: For lyophilized recombinant proteins, standardize reconstitution methods using sterile PBS containing at least 0.1% serum albumin to maintain stability, similar to approaches used for other recombinant mouse proteins

What are effective approaches for generating mouse models to study KIAA1107 function?

Based on experiences with other KIAA family proteins, researchers should consider:

• CRISPR/Cas9 gene editing: This approach has been successfully used to generate mouse mutant alleles for mKiaa1211. When designing CRISPR targets, consider:

  • Targeting conserved exons that are present across multiple splice variants

  • Avoiding regions that might affect related family members

  • Including appropriate genotyping strategies

• Hypomorphic vs. complete knockout models: The example of mKiaa1211 mutant mice is instructive, as a CRISPR-generated mutation resulted in a hypomorphic allele with ~60% reduction in mRNA levels rather than complete elimination. Researchers should characterize expression levels in their models and be prepared to interpret partial loss-of-function phenotypes

• Phenotypic analysis timeline: For proteins like mKiaa1211, some phenotypes (such as adenoma tumor development) only became apparent after 5-6 months of aging. Long-term observation protocols should be established for KIAA1107 models

• Tissue-specific conditional knockouts: Given the specific expression pattern of KIAA1107 in brain regions, consider Cre-lox systems targeting relevant tissues to avoid potential embryonic lethality and enable tissue-specific functional studies

How should researchers interpret contradictory data in KIAA1107 functional studies?

Uncharacterized proteins often present contradictory findings. When faced with such scenarios:

• Examine genetic compensation: Check for potential upregulation of paralogous genes. For example, when studying mKiaa1211 knockout models, researchers examined whether mKiaa1211L (the paralog) showed compensatory upregulation. For KIAA1107, identify and monitor potential paralogous genes

• Consider developmental timing: Expression levels of KIAA family proteins can vary significantly across developmental stages. In mKiaa1211, expression was highest around E12.5 in heart development but scarcely detectable in adult hearts. Temporal analysis is critical for accurate interpretation

• Evaluate hypomorphic vs. null phenotypes: The mKiaa1211 mouse model demonstrated that a hypomorphic allele with 60% reduction in expression showed no obvious phenotype. This suggests that some KIAA family proteins may require near-complete loss of function to observe phenotypes, or redundant mechanisms may compensate for partial loss

• Integrate tissue-specific analyses: Given the tissue-specific expression patterns of KIAA1107, conflicting results might stem from tissue heterogeneity. Isolate specific tissues for analysis rather than using whole-organ approaches

What methodological approaches are recommended for studying KIAA1107 in neurological disease models?

Given KIAA1107's association with Multiple Sclerosis brain lesions, researchers should consider:

• Expression correlation studies: Compare KIAA1107 expression levels with disease progression markers in MS models. Use qPCR and in situ hybridization to quantify and localize expression changes

• White matter-specific analyses: Since KIAA1107 shows increased expression specifically in white matter of MS lesions, develop protocols that:

  • Separate white matter from gray matter in tissue samples

  • Track protein expression changes during lesion formation

  • Correlate with inflammatory markers

• Cell type-specific expression: Determine which neural cell types (oligodendrocytes, astrocytes, microglia) express KIAA1107 using:

  • Single-cell RNA sequencing

  • Immunohistochemistry with cell type-specific markers

  • Cell sorting followed by expression analysis

• Functional rescue experiments: In disease models showing altered KIAA1107 expression, attempt rescue through:

  • Viral delivery of wild-type KIAA1107

  • Small molecule modulators of pathways potentially involving KIAA1107

  • Genetic approaches to normalize expression levels

What are the best practices for reconstitution and storage of recombinant mouse KIAA1107?

Based on protocols for other recombinant mouse proteins:

• Reconstitution protocol:

  • Reconstitute lyophilized protein at 100 μg/mL in sterile PBS

  • Include at least 0.1% human or bovine serum albumin as a stabilizer

  • Allow complete dissolution before aliquoting

• Storage recommendations:

  • Use a manual defrost freezer

  • Avoid repeated freeze-thaw cycles

  • Store reconstituted protein in single-use aliquots

  • Consider carrier-free formulations for applications where BSA might interfere

• Stability considerations:

  • Monitor protein activity over time with functional assays

  • Validate protein integrity using gel electrophoresis after storage periods

  • Consider adding protease inhibitors for long-term storage

What expression systems are optimal for producing recombinant mouse KIAA1107?

Although specific information on KIAA1107 expression systems is not provided in the search results, researchers should consider:

• Mammalian expression systems: For a complex protein like KIAA1107 with potential post-translational modifications, mammalian systems (CHO, HEK293) may provide more native-like processing

• Bacterial systems with solubility tags: If full-length protein expression proves challenging, consider:

  • Expression of functional domains separately

  • Fusion with solubility-enhancing tags (MBP, SUMO, GST)

  • Codon optimization for E. coli expression

• Baculovirus-insect cell systems: For improved folding and moderate post-translational modifications compared to bacterial systems

How can researchers effectively design functional assays for an uncharacterized protein like KIAA1107?

When working with uncharacterized proteins:

• Domain-based prediction approaches:

  • Focus on the DUF4596 domain present in KIAA1107 for initial functional hypotheses

  • Use protein-protein interaction prediction tools to identify potential binding partners

  • Consider homology with other proteins containing similar domains

• Expression-guided assays:

  • Given KIAA1107's expression in neural tissue and association with MS lesions, design assays related to:

    • Myelination processes

    • Inflammatory responses

    • Cell survival under stress conditions

• Developmental timing considerations:

  • Based on expression patterns of related KIAA family proteins like mKiaa1211, which shows specific developmental expression, design assays examining:

    • Neural development stages

    • Cell differentiation processes

    • Stage-specific protein interactions

What emerging technologies could advance our understanding of KIAA1107 function?

Several cutting-edge approaches could accelerate KIAA1107 research:

• Proximity labeling approaches: BioID or APEX2 fusion proteins to identify proximal interacting partners in relevant cell types

• Cryo-EM structural analysis: Determine three-dimensional structure of KIAA1107, particularly focusing on the DUF4596 domain

• Single-cell proteomics: Map KIAA1107 expression at the single-cell level within complex tissues like brain regions where it shows specific expression patterns

• CRISPR activation/inhibition screens: Modulate KIAA1107 expression in cellular models to identify phenotypic changes and potential pathway involvements

How should researchers approach comparative studies between human and mouse KIAA1107?

For meaningful cross-species comparisons:

• Sequence homology analysis: Determine conservation levels between human and mouse orthologs, particularly in functional domains

• Expression pattern comparison: Compare tissue-specific expression patterns between species, with particular attention to:

  • Brain region specificity

  • Developmental timing differences

  • Disease-relevant tissues

• Functional conservation testing: Determine whether mouse KIAA1107 can rescue phenotypes in human cell models with KIAA1107 knockdown

• Disease model relevance: Establish whether mouse models recapitulate expression changes observed in human pathological conditions like Multiple Sclerosis