Validation requires a multi-step approach:
Cross-reference antibody datasheets: Confirm immunogen sequence alignment with the target protein (e.g., RBM48’s C-terminal peptide: FLQTNPTGNEIMIGPLLPDISKVDMHDDSLNTTANLIRHKLKEVISSVPK ).
Use positive/negative controls: Compare lysates from tissues/cell lines with known RBM48 expression (e.g., human cell lines) against knockout models. For example, maize rbm48 mutants showed no detectable transcripts via RT-PCR, validating antibody specificity in plant models .
Assess band specificity: Verify the antibody detects a single band at the predicted molecular weight (~42 kDa in humans ). Discrepancies may indicate cross-reactivity or post-translational modifications.
Methodological rigor in IHC requires:
Isotype controls: Use rabbit IgG at the same concentration as the primary antibody to rule out nonspecific binding .
Tissue-specific controls: Compare staining in tissues with high RBM48 expression (e.g., human liver) versus low-expression tissues (e.g., maize endosperm mutants ).
Pre-absorption assays: Pre-incubate the antibody with excess immunogen peptide; staining should be abolished .
RBM48 antibodies designed against human epitopes may exhibit cross-reactivity in other species depending on sequence conservation:
High homology (93%): Reliable detection in dog, pig, and rat tissues .
Moderate homology (86%): Requires validation in mouse, horse, and guinea pig via knockout models (e.g., maize rbm48-umu1 mutants ).
Low homology (83% in zebrafish): Likely requires species-specific antibody development.
A robust workflow includes:
Genetic models: Use CRISPR-Cas9 to generate RBM48 knockout cell lines (e.g., maize rbm48-umu1 ).
Splicing assays: Perform RNA-seq to quantify U12 intron retention (e.g., ΔPSO > 20% in mutants ).
Co-immunoprecipitation (Co-IP): Identify interacting spliceosome components like U2AF or RGH3 .
Address contradictions systematically:
Buffer optimization: Compare antibody performance in PBS (pH 7.2) vs. proprietary buffers .
Epitope masking: Test antigen retrieval methods (e.g., heat-induced epitope retrieval for IHC-Paraffin ).
Batch variability: Revalidate using independent antibody lots (e.g., Novus Biologicals vs. OriGene ).
Lysate preparation: Use mild detergents (e.g., 1% NP-40) to preserve RNA-protein interactions critical for RBM48’s splicing function .
Antibody coupling: Immobilize RBM48 antibodies on Protein A/G beads for 2 hours at 4°C .
Validation: Confirm interactions via Western blot (e.g., detect ARMC7 in eluates ).
Signal amplification: Use tyramide-based systems for IHC in maize endosperm .
Multiplexing: Combine with RNA FISH to colocalize RBM48 with U12 introns .
Cross-linking: Fix tissues with formaldehyde to stabilize RNA-protein complexes .