Respiratory Syncytical Virus matrix protein M2-1

Creative Biolabs’ Respiratory syncytial virus M2-1 antibody provides researchers with a valuable tool for accurately detecting and studying this key viral protein. This enables a range of applications, from basic research into Respiratory Syncytial Virus biology to the development of new diagnostic assays and therapeutic interventions.

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Introduction of Respiratory syncytial virus M2-1

Human orthopneumovirus, an enveloped RNA pathogen of genus Orthopneumovirus (family Pneumoviridae, order Mononegavirales), drives life-threatening pathobronchiolar inflammation in pediatric and immunodeficient cohorts. Central to its transcriptional regulation, the virally encoded M2-1 tetrameric phosphoprotein—a zinc-finger topological modulator—orchestrates transcriptional elongation fidelity without influencing initiation complex formation, termination signal recognition (GE signals), or 5’ mRNA capping through guanylyltransferase activity.

Fig. 1 Human Respiratory Syncytial Virus.Distributed under CC BY 2.0, from Wiki, without modification

Mechanistic studies reveal M2-1’s critical role in enabling transcriptase processivity: while the viral polymerase synthesizes truncated mRNAs (<500 nt) in its absence, M2-1 facilitates readthrough of intergenic cis-acting signals to produce full-length transcripts. Paradoxically, this factor also promotes bicistronic mRNA accumulation via leaky scanning of gene-end signals—a phenomenon initially overestimated due to artifactual findings from a hyperprocessive L mutant polymerase. Cryo-EM reconstructions demonstrate M2-1’s tetrameric zinc-binding domains stabilize nascent RNA-polymerase interactions during elongation, while remaining inert during replicative RNA synthesis. This functional dichotomy aligns with biochemical evidence: M2-1 co-sediments exclusively with mRNA-loaded transcriptase complexes, not genomic ribonucleocapsid fractions.

Biophysical analyses have elucidated the structural-functional topology of M2-1, a transcriptional cofactor comprising three modular domains interconnected by flexible linkers. The N-terminal CCCH zinc finger motif mediates RNA chaperoning and elongation, while a central α-helical tetramerization domain drives homotetrameric assemblies. A globular core domain further stabilizes RNA interactions via conserved basic residues. Recruitment to the viral polymerase occurs through quaternary interactions with phosphoprotein (P), facilitated by tetramer symmetry matching. Cryo-EM reconstructions suggest conformational plasticity between compact (RNA-bound) and extended (RNA-free) states modulates transcriptional processivity.

Fig. 2 Experimental design to identify RNA bound by M2-1.^1,3

Notably, human metapneumovirus (HMPV) M2-1 retains structural conservation—including the CCCH motif and tetramerization interface—but diverges functionally: dispensable for in vitro transcription/replication yet indispensable in murine models (ΔM2-1 shows complete replication arrest). This dichotomy implies Respiratory Syncytial Virus M2-1 has evolutionarily co-opted auxiliary roles, potentially coupling transcriptional regulation with innate immune antagonism through dsRNA sequestration.

Antibodies Against Respiratory Syncytial Virus M2-1

Immunofluorescence temporal mapping using epitope-specific probes revealed spatiotemporal dynamics of the M2-1 transcriptional cofactor during respiratory syncytial virus infection. Early-stage viral replication factories—termed viroplasms—harbor viral ribonucleoprotein complexes (N, P, L) that coalesce into transcriptionally active inclusion bodies (IBs) over time. M2-1 exhibits biphasic localization: initially concentrated within nascent IB precursors, later partitioning into late-stage IB-associated genome synthesis compartments (IBAGs) while maintaining cytoplasmic diffusion.

Intriguingly, parallel staining of recombinant HA-M2-1 Respiratory Syncytial Virus-infected A549 cells using anti-HA versus anti-M2-1 monoclonal antibodies (mAbs) uncovered epitope accessibility gradients. At 6 hpi, both mAbs co-localized to punctate viroplasms confirming M2-1’s association with primary replication hubs. By 12 hpi, anti-HA mAbs predominantly marked IBAG-localized M2-1 (92% signal overlap with N protein), while pan-M2-1 mAbs additionally detected diffuse cytoplasmic pools (37% non-overlapping signal). This divergence amplified at 24 hpi, with HA-tagged M2-1 sequestered entirely within IBs (98% co-localization), versus endogenous M2-1 exhibiting pan-cytoplasmic distribution (62% diffuse signal).

Fig. 3 M2-1 localizes to viral inclusions and the cytoplasm at various times post infection.^1,3

Paradoxically, all cellular M2-1 contained the HA tag, suggesting conformational masking of the exogenous epitope in cytoplasmic fractions. These data imply IB-localized M2-1 adopts a structural conformation exposing the HA tag, while diffusely distributed molecules bury this epitope—likely through RNA-mediated oligomeric rearrangements.

Why Choose Us?

Creative Biolabs is committed to providing researchers with high-quality, reliable antibodies and exceptional customer support. Our Respiratory syncytial virus M2-1 antibody is rigorously validated to ensure specificity and performance in a variety of applications.

• High Specificity and Sensitivity: Our antibodies are designed to minimize cross-reactivity with other proteins, ensuring accurate and reliable detection of the target protein.
• Broad Application Compatibility: Creative Biolabs antibodies are validated for use in a wide range of applications, including Western blot, ELISA, immunofluorescence, and immunohistochemistry.
• Stringent Quality Control: Each antibody undergoes rigorous testing to ensure consistent performance and reproducibility.

For more information about Creative Biolabs' Respiratory Syncytial Virus M2-1antibodies and services, please contact us.

REFERENCES

1. Braun, Molly R., et al. "Respiratory syncytial virus M2-1 protein associates non-specifically with viral messenger RNA and with specific cellular messenger RNA transcripts." PLoS pathogens 17.5 (2021): e1009589.
2. Bouillier, Camille, et al. "The Interactome analysis of the Respiratory Syncytial Virus protein M2-1 suggests a new role in viral mRNA metabolism post-transcription." Scientific Reports 9.1 (2019): 15258.
3. Distributed under Open Access license CC BY 4.0, without modification.