You have no items in your shopping cart.
mScarlet Fluorescent Protein: Bright Red Reporter for Live-Cell Imaging, Fusion Protein Studies and Advanced Biomedical Research
mScarlet fluorescent protein is a bright monomeric red fluorescent protein widely used for live-cell imaging, fusion protein labeling, reporter gene assays, CRISPR workflows, and advanced biomedical research.
Overview
mScarlet fluorescent protein is a bright monomeric red fluorescent protein widely used for live-cell imaging, fusion protein labeling, reporter gene assays, CRISPR workflows, and advanced biomedical research. Biorbyt provides a range of anti-mScarlet antibodies---including goat, rabbit, and mouse, polyclonal and monoclonal options---suitable for Western blot (WB), immunofluorescence (IF), immunohistochemistry (IHC), immunoelectron microscopy (IEM), and reporter validation workflows.
What Is mScarlet?
mScarlet fluorescent protein is a bright monomeric red fluorescent protein (RFP) derived from the DsRed family. It consists of 232 amino acids and has a molecular weight of approximately 26.4 kDa. Recognized as one of the brightest monomeric RFPs currently available, mScarlet exhibits a quantum yield of approximately 70%, contributing to its exceptionally strong fluorescence signal.
Its monomeric structure helps reduce artificial protein clustering when fused to a protein of interest. This makes mScarlet particularly valuable when researchers need to preserve accurate protein localization, intracellular trafficking, or dynamic cellular behavior.
mScarlet, mScarlet-I and mScarlet3
mScarlet has evolved into several optimized variants. While the original mScarlet is known for its exceptional brightness, mScarlet-I was developed to improve maturation speed, and mScarlet3 was further engineered for enhanced folding efficiency, intracellular stability, and long-term imaging performance.
Variant | Main Advantage | Typical Applications |
|---|---|---|
mScarlet | Extremely bright monomeric red fluorescence | Fusion protein labeling, red fluorescence imaging |
mScarlet-I | Faster maturation while maintaining strong brightness | Reporter gene assays, CRISPR workflows, rapid cell tracking |
mScarlet3 | Improved folding, stability, and long-term performance | Long-term imaging, stem cell studies, neuronal imaging |
These variants share highly conserved amino acid sequences and structural features, which is important when selecting anti-mScarlet antibodies for WB, IF, ICC, or IHC applications.
mScarlet vs mCherry, tdTomato and DsRed
mScarlet belongs to the broader DsRed-derived red fluorescent protein family, which includes DsRed, dTomato, tdTomato, mCherry, and related engineered variants. These proteins share a conserved β-barrel structure and core chromophore environment, but differ in brightness, maturation speed, oligomerization state, photostability, antibody recognition, and suitability for fusion protein or live-cell imaging workflows.
Researchers usually compare mScarlet with other red fluorescent proteins based on structure, excitation and emission wavelengths, signal intensity, antibody support, and application compatibility. Understanding these differences helps researchers choose the most appropriate red fluorescent protein for imaging, reporter assays, CRISPR workflows, cell tracking, or antibody-based validation.
Protein Name | Structure | Excitation / Emission | Key Features | Recommended Applications |
|---|---|---|---|---|
mScarlet | Monomer | 569 / 594 nm | Very bright monomeric RFP; high quantum yield; strong signal with low structural interference | Fusion protein labeling, live-cell imaging, reporter gene assays, CRISPR validation, gene therapy |
DsRed | Tetramer | 558 / 583 nm | First-generation red fluorescent protein; strong fluorescence but tetrameric structure may interfere with fusion protein behavior | Historical RFP studies, lineage tracing, basic fluorescent labeling, RFP family comparison |
Tandem dimer | 554 / 581 nm | Extremely bright and photostable; contains two fluorescent chromophores | Cell tracking, in vivo imaging, reporter assays, whole-animal imaging | |
Monomer | 587 / 610 nm | Well-established monomeric RFP; broad antibody support and extensive validation history | Routine imaging, fusion protein studies, antibody-based detection workflows |
Among currently available monomeric red fluorescent proteins, mScarlet and its derivatives provide one of the strongest combinations of brightness, maturation efficiency, and compatibility with fusion protein applications. This balance has contributed to their growing adoption in cell biology, gene editing, imaging, gene therapy, and spatial biology.
Compared with mCherry, mScarlet generally provides stronger fluorescence, which can improve detection in low-expression systems such as primary cells, stem cells, organoids, neuronal cultures, and CRISPR-engineered models. However, mCherry remains valuable when extensive antibody validation and long-established protocols are priorities.
Compared with tdTomato, mScarlet may be less bright in some direct fluorescence applications, but its monomeric structure makes it more suitable for fusion protein studies where tandem dimer architecture may interfere with protein localization, trafficking, or biological function.
Applications of mScarlet
1. mScarlet for Live-Cell Imaging and Protein Localization
mScarlet is widely used for live-cell imaging because its bright red fluorescence enables clear visualization of cellular structures and dynamic biological processes. Its red emission channel is compatible with green and cyan fluorescent proteins, making it suitable for dual-color and multicolor imaging experiments.
Common applications include:
- Confocal microscopy
- Time-lapse imaging
- Cell migration analysis
- Protein trafficking studies
- Organelle imaging
- Subcellular localization
- Multicolor fluorescence imaging
- Longitudinal cell tracking
2. mScarlet for Fusion Protein Labeling and Localization Studies
Because mScarlet is monomeric, it can be fused to a protein of interest to monitor localization, movement, or expression while minimizing artificial clustering.
Typical studies include:
- Membrane protein localization
- Cytoskeletal dynamics
- Nuclear transport
- Organelle targeting
- Protein trafficking
- Protein-protein interaction workflows
- Fluorescent tag validation
mScarlet fusion protein systems are especially useful for proteins sensitive to structural interference or dynamic localization.
3. mScarlet Reporter Gene, CRISPR and AAV Applications
mScarlet and mScarlet-I are frequently used as red fluorescent reporter genes in mammalian expression systems. Their strong red fluorescence allows researchers to identify successfully transfected, transduced, or gene-edited cells efficiently.
Typical workflows include:
- Plasmid transfection monitoring
- Lentiviral expression systems
- CRISPR knock-in validation
- Stable fluorescent cell line generation
- Promoter activity studies
- Cell sorting and enrichment workflows
- Viral vector development
In AAV-based gene delivery studies, mScarlet reporter constructs can evaluate transduction efficiency, monitor transgene expression, and assess spatial reporter distribution in vivo. For example, AAV8-mScarlet reporter vectors have been used in retinal gene therapy to visualize photoreceptor transduction and track expression in non-human primate models.
Moreover, mScarlet reporters can be combined with single-cell RNA sequencing and spatial transcriptomic approaches, enabling researchers to link fluorescence-based tracking with high-resolution molecular profiling, study cellular heterogeneity, and analyze tissue-specific expression patterns.
4. mScarlet in Tumor Imaging and Immune Microenvironment Research
mScarlet-labeled cells are used in cancer biology and immune-oncology studies to monitor tumor growth, metastasis, drug response, and cell movement.
In tumor immune microenvironment studies, mScarlet reporters can be combined with immune markers such as CD68, CD163, CD206, IBA1, F4/80, CD11b, CD3, CD4, CD8, or FOXP3 to evaluate immune cell infiltration, macrophage distribution, T cell localization, and tissue immune remodeling.
Anti-mScarlet Antibodies for WB, IF and IHC
Although mScarlet fluorescence can often be directly visualized, anti-mScarlet antibodies remain important for Western blot (WB), immunofluorescence (IF), immunocytochemistry (ICC), immunohistochemistry (IHC), tissue sections, and low-expression reporter validation.
Anti-mScarlet antibodies can support:
- Signal amplification in low-expression systems
- Detection of mScarlet-tagged fusion proteins
- Western blot validation of fluorescent tags
- Fixed-cell IF and ICC workflows
- IHC detection in tissue sections
- Reporter expression confirmation
When selecting an anti-mScarlet antibody, researchers should check species host, clonality, application validation, immunogen design, and whether the antibody has been tested against mScarlet, mScarlet-I, mScarlet3, or related red fluorescent proteins.
Recommended mScarlet Antibodies
Product Name | SKU | Applications | Size / Format | Price |
|---|---|---|---|---|
mScarlet Goat Polyclonal Antibody | IEM, IF, IHC-Fr, IHC-P, WB | 100 μg | $300 | |
mScarlet Rabbit Polyclonal Antibody | WB | 50 μl | $250 | |
mScarlet Rabbit Polyclonal Antibody | IHC, WB | 50 μl | $250 | |
mScarlet Mouse Monoclonal Antibody | WB | 50 μl | $250 |
When choosing an anti-mScarlet antibody, researchers should match the antibody format to the intended workflow. Mouse monoclonal antibodies are often preferred for high-specificity Western blot validation or fusion tag detection, while rabbit polyclonal antibodies may provide stronger signal for low-abundance targets. Goat polyclonal antibodies with IF or IHC validation can be useful for fluorescence imaging, tissue staining, and histological workflows. For experiments involving mScarlet-I or mScarlet3, product-specific validation should always be reviewed, although many anti-mScarlet antibodies may recognize these variants because of their high sequence conservation. Combining direct fluorescence imaging with antibody-based detection can provide a more complete assessment of reporter expression and localization.
Frequently Asked Questions
1. Is mScarlet brighter than mCherry?
Yes. mScarlet is generally brighter than mCherry and is recognized as one of the brightest monomeric red fluorescent proteins currently available. Its high quantum yield (~70%) contributes to strong fluorescence signals, making it particularly useful for low-expression systems, sensitive imaging applications, and reporter gene assays.
2. What are the differences among mScarlet, mScarlet-I, and mScarlet3?
All three proteins belong to the mScarlet family but were optimized for different experimental needs.
- mScarlet: Original variant with exceptionally bright red fluorescence.
- mScarlet-I: Faster maturation while maintaining high brightness.
- mScarlet3: Improved folding efficiency, intracellular stability, and long-term imaging performance.
Researchers typically choose mScarlet-I when rapid fluorescence detection is important and mScarlet3 for demanding applications such as stem cell studies, neuronal imaging, or long-term live-cell imaging.
3. Is mScarlet monomeric?
Yes. mScarlet is a monomeric red fluorescent protein. This characteristic makes it particularly suitable for fusion protein applications because it minimizes the risk of artificial protein aggregation or altered intracellular localization that can occur with multimeric fluorescent proteins.
4. What are the excitation and emission wavelengths of mScarlet?
mScarlet excitation and emission maxima are approximately:
- Excitation maximum: ~569 nm
- Emission maximum: ~594 nm
These spectral properties make mScarlet well suited for red fluorescence imaging and multicolor experiments alongside GFP, EGFP, CFP, YFP, and other fluorescent proteins.
5. What applications is mScarlet commonly used for?
mScarlet is widely used in live-cell imaging, protein localization studies, fusion protein labeling, reporter gene assays, CRISPR validation workflows, cell tracking, multicolor fluorescence imaging, viral vector and AAV reporter studies, gene therapy research, and tumor immune microenvironment studies. Its combination of high brightness and monomeric behavior makes mScarlet fluorescent protein versatile across many areas of cell and molecular biology.
6. Can anti-mScarlet antibodies detect mScarlet-I and mScarlet3?
In many cases, yes. Because mScarlet-I and mScarlet3 share highly conserved amino acid sequences and structural features with the original mScarlet protein, many anti-mScarlet antibodies can recognize these variants. However, researchers should always review product-specific validation data for intended applications such as Western blotting, immunofluorescence, immunocytochemistry, or immunohistochemistry.
7. Is mScarlet suitable for fusion protein studies?
Yes. One of the major advantages of mScarlet is its monomeric structure. When fused to a protein of interest, mScarlet is less likely to interfere with protein function, intracellular trafficking, or subcellular localization compared with multimeric fluorescent proteins. This makes it a popular choice for fusion protein labeling and protein localization studies.
8. Can mScarlet be combined with GFP or EGFP?
Yes. mScarlet is frequently used in dual-color and multicolor imaging experiments alongside GFP, EGFP, CFP, YFP, mTurquoise, and other fluorescent proteins. Its red emission spectrum is well separated from green and cyan fluorescent proteins, facilitating simultaneous visualization of multiple biological targets.
9. When should I use antibody detection instead of direct fluorescence?
Direct mScarlet fluorescence is typically sufficient for live-cell imaging, reporter screening, and cell tracking experiments. Antibody-based detection may be preferred when researchers require signal amplification, fixed-cell imaging, Western blot validation, immunofluorescence (IF), immunocytochemistry (ICC), immunohistochemistry (IHC), or detection of low-expression reporter proteins.
10. Is mScarlet better than tdTomato?
The answer depends on the application. tdTomato is generally brighter because it contains two fluorescent chromophores within a tandem dimer structure. However, this larger structure may not be ideal for fusion protein studies. mScarlet offers a combination of high brightness and true monomeric behavior, making it particularly useful for protein localization studies, fusion protein labeling, and reporter gene applications where minimizing structural interference is important.
11. Why is mScarlet popular for gene therapy and AAV reporter studies?
mScarlet provides strong red fluorescence while maintaining a compact monomeric structure, making it a useful reporter for viral vector development and gene therapy research. Researchers use mScarlet reporters to monitor transduction efficiency, track transgene expression, evaluate AAV vector performance, and visualize reporter expression in vivo. Recent studies have also employed AAV8-mScarlet reporter systems in retinal gene therapy research to assess photoreceptor transduction and transgene expression in vivo.
Conclusion
mScarlet fluorescent protein is a powerful monomeric red fluorescent protein for live-cell imaging, fusion protein labeling, reporter gene assays, CRISPR workflows, and advanced cell tracking. Its high brightness, monomeric structure, and compatibility with mammalian expression systems make it a strong alternative to earlier red fluorescent proteins such as mCherry and tdTomato.
With optimized variants such as mScarlet-I and mScarlet3, researchers can choose versions better suited for faster maturation, improved folding, or long-term imaging. Beyond routine imaging, mScarlet is increasingly valuable in advanced biomedical research, including AAV reporter studies, gene therapy research, in vivo imaging, and single-cell or spatial transcriptomic workflows.
Combined with appropriate anti-mScarlet antibody validation, mScarlet provides a flexible platform for both real-time fluorescence imaging and downstream experimental confirmation.
Reference
- Bindels DS, Haarbosch L, van Weeren L, et al. mScarlet: a bright monomeric red fluorescent protein for cellular imaging. Nat Methods. 2017;14(1):53--56. doi:10.1038/nmeth.4074.
- Gadella TWJ Jr, van Weeren L, Stouthamer J, et al. mScarlet3: a brilliant and fast-maturing red fluorescent protein. Nat Methods. 2023;20(4):541--545. doi:10.1038/s41592-023-01809-y.
- Garcia‑Parajo MF, Koopman M, van Dijk EM, et al. The nature of fluorescence emission in the red fluorescent protein DsRed, revealed by single-molecule detection. Proc Natl Acad Sci U S A. 2001;98(25):14392--14397. doi:10.1073/pnas.251525598.
- Baird GS, Zacharias DA, Tsien RY. Biochemistry, mutagenesis, and oligomerization of DsRed, a red fluorescent protein from coral. Proc Natl Acad Sci U S A. 2000;97(22):11984--11989. doi:10.1073/pnas.97.22.11984.
- Fink R, Imai S, Gockel N, et al. PinkyCaMP: an mScarlet-based calcium sensor with enhanced brightness, photostability and multiplexing capabilities. Nat Methods. 2026;23(5):998--1010. doi:10.1038/s41592-026-03065-2. PMID: 42032066; PMCID: PMC13167472.
- Sourd C, Quinn J, John MC, et al. Single-cell and spatial transcriptomic analyses of gene therapy-associated retinal inflammation in non-human primates. Mol Ther Adv. 2026;34(2):201726. doi:10.1016/j.omta.2026.201726. PMID: 42137601; PMCID: PMC13148909.