Figure 1
SAGE procedure. A population of mRNA transcripts is first extracted from a tissue or cell type, and the mRNA is reverse transcribed to produce cDNA. A series of enzyme digestions, ligations, and PCR amplifications are performed as shown. As the 3′ end of the cDNA is anchored during the first digestion, the tags are extracted from the 3′-most anchoring enzyme site, an important fact to consider when producing tag mappings. The procedure produces 14-bp SAGE tags derived from the sequence of the mRNA transcripts, the frequency of which represents the expression level of the transcripts.
