Serial analysis of gene expression (SAGE) is a technique that allows the quantitave evaluation of the level of gene expression in a cell. Developed in the laboratory of Bert Vogelstein in 1995, this technique is based on the production and sequencing, and count of small cDNA pieces called tags which are subsequently assigned to corresponding genes. Extensive sequencing, deep bioinformatic knowledge, and powerful computer software are required to assemble and analyze results from SAGE experiments. This is most likely one of the reasons of the limited use of this sensitive technique in academic research laboratories.

In a typical SAGE experiment, messenger RNA (mRNA) that are naturally tagged by poly (A), are isolated from control and experimental cells and converted into double-stranded cDNAs using biotin-labeled oligo (dT) primers. The cDNAs are digested with specific restriction enzymes to produce small biotin...