Practice question

Northern blotting preserves information about transcript length and abundance, making it particularly suited to study RNA splicing regulation. Pre-mRNA can undergo alternative exon inclusion, intron retention, exon skipping, or use of alternative 5' and 3' splice sites, generating multiple mature mRNAs of differing sizes from single gene. Formaldehyde agarose electrophoresis resolves these size variants, and probe hybridization reveals pattern of isoforms. Emergence of larger bands exclusively under induced condition indicates activation of splicing factors or retention events, insight not obtainable from Western analysis of proteins or Southern analysis of genomic DNA.