Methyltransferase-like 3 (METTL3) is an enzyme that modifies RNA molecules. A METTL3 antibody is a molecular tool enabling scientists to identify and investigate the METTL3 protein within biological samples. This allows for a deeper understanding of its presence, location, and interactions in various cellular processes.
The Function of the METTL3 Protein
METTL3 acts as a key component of the N6-methyladenosine (m6A) methyltransferase complex, often referred to as the “writer” complex for m6A modifications on RNA. This enzyme, along with METTL14 and Wilms’ tumor 1-associating protein (WTAP), forms the core machinery responsible for depositing m6A marks on messenger RNA (mRNA) and other RNA types. METTL3 itself functions as the catalytic subunit, transferring a methyl group from S-adenosylmethionine (SAM) to adenosine residues within specific RNA sequences, typically the RRACH motif.
The m6A modification is the most common internal modification found in eukaryotic mRNA, influencing various aspects of RNA metabolism. These modifications can affect RNA stability, RNA splicing, and mRNA export from the nucleus to the cytoplasm. m6A can also impact mRNA translation, affecting protein production from RNA templates.
METTL3’s role extends beyond its methyltransferase activity, as it can also influence mRNA translation by interacting with translation initiation factors, sometimes independent of its catalytic function. This dual functionality highlights its complex involvement in controlling gene expression. The regulation of m6A levels by METTL3 is important for maintaining normal cellular functions, given its broad impact on RNA processing and protein synthesis.
Research Applications of METTL3 Antibodies
METTL3 antibodies are widely used in various laboratory techniques to characterize the protein. Western Blotting (WB) is a common application where these antibodies help detect the presence and approximate molecular weight of the METTL3 protein in cell lysates or tissue extracts. This technique also allows researchers to assess the relative abundance of METTL3 protein in different samples, providing insights into its expression levels under various conditions.
Immunohistochemistry (IHC) and Immunofluorescence (IF) employ METTL3 antibodies to visualize the protein’s localization within cells or tissues. In IHC, antibodies are applied to tissue sections to reveal METTL3 distribution in a preserved tissue context. For IF, antibodies are labeled with fluorescent dyes, enabling researchers to observe METTL3’s subcellular location, such as in the nucleus, using a fluorescence microscope.
Immunoprecipitation (IP) and Chromatin Immunoprecipitation (ChIP) are techniques that utilize METTL3 antibodies to isolate the protein and identify its interacting partners or bound nucleic acids. In IP, the antibody captures METTL3 from a complex mixture, allowing for the subsequent analysis of other proteins that associate with METTL3. ChIP, a related technique, uses the antibody to pull down METTL3-bound DNA or RNA, which helps researchers identify the specific genetic regions or RNA molecules that METTL3 interacts with or modifies. These methods provide detailed information about METTL3’s molecular associations and its functional network within the cell.
METTL3’s Role in Disease and Development
Dysregulation of METTL3 is increasingly linked to various human diseases, particularly different types of cancer. In acute myeloid leukemia (AML), elevated METTL3 expression is observed, where it promotes the translation of oncogenic transcripts like c-MYC and BCL2, contributing to disease progression and resistance to therapy. Similarly, METTL3 overexpression has been noted in lung adenocarcinoma, where it enhances the translation of proteins such as EGFR and TAZ, thereby promoting cancer cell growth, survival, and invasion.
METTL3 also plays a role in other cancers, including hepatocellular carcinoma (HCC), where it can promote tumorigenesis by methylating and stabilizing certain RNA molecules. Its involvement extends to glioblastoma, prostate cancer, and cervical cancer, often acting as an oncogene by influencing cell proliferation, migration, and invasion. However, the role of METTL3 can be context-dependent, sometimes exhibiting tumor-suppressive functions in specific cancer types like renal cell carcinoma.
Beyond disease, METTL3 is recognized for its importance in normal biological processes, including embryonic development. Studies indicate that METTL3 is an an essential gene for early embryonic survival in mice, with its deletion leading to embryonic lethality. METTL3 also contributes to the immune response by modulating immune cell differentiation, activation, and function. For instance, it influences T cell maturation and differentiation and impacts macrophage polarization, demonstrating its broad influence on cellular homeostasis.
Selecting and Validating a METTL3 Antibody
When selecting a METTL3 antibody for research, clonality is a primary consideration. Monoclonal antibodies are derived from a single B cell clone, offering high specificity and consistent performance across different batches. Polyclonal antibodies, conversely, are a mixture of antibodies from multiple B cell clones, recognizing various epitopes on the target protein, which can lead to higher signal but also a greater chance of off-target binding. Monoclonal antibodies are generally preferred for reproducibility, while polyclonal antibodies might be useful for detecting low-abundance proteins.
The host species of the antibody (e.g., rabbit, mouse) and its reactivity with the intended experimental organism (e.g., human, mouse, rat) are also important. Researchers must ensure the antibody is validated to detect METTL3 in their specific model system to avoid inconclusive results. Many manufacturers provide information on tested species reactivity, which can guide this selection.
Application validation is another consideration, as an antibody performing well in one technique may not be suitable for another. A METTL3 antibody validated for Western Blotting might not work for Immunohistochemistry or Immunoprecipitation, and vice-versa. Checking the manufacturer’s data sheets for validation in the specific application (e.g., WB, IHC, IF, IP, ChIP) is necessary. Looking for evidence of validation using knockout (KO) or knockdown (KD) models provides strong assurance of an antibody’s specificity, as these experiments confirm the signal observed is from METTL3 and not non-specific binding.