Practice question

In Serial Analysis of Gene Expression, mRNA isolation is a prerequisite for quantitative cDNA synthesis and tag generation. Biotinylated oligo(dT) primers anneal specifically to the poly(A) tails of mature eukaryotic mRNAs, allowing selective capture on streptavidin-coated magnetic beads. This immobilization anchors the template for double-stranded cDNA synthesis and subsequent restriction digestion with anchoring enzyme NlaIII. By tethering mRNA through poly(A)-oligo(dT) interaction, the protocol ensures orientation-specific processing, efficient removal of ribosomal and transfer RNA contaminants, and generation of uniform tags representative of cellular transcriptome complexity.