SELECTIVE AMPLIFICATION VIA BIOTIN-MEDIATED AND RESTRICTION-MEDIATED ENRICHMENT (SABRE), A NOVEL SELECTIVE AMPLIFICATION PROCEDURE FOR DETECTION OF DIFFERENTIALLY EXPRESSED MESSENGER-RNAS

We present a novel subtractive enrichment protocol for the identificat ion of differentially expressed mRNA species. This procedure, called S ABRE (selective amplification via biotin- and restriction-mediated enr ichment), uses selective streptavidin-biotin affinity and restriction enzyme site reconstitution to enrich for cDNA species more abundant in one population than in another, Analysis of liver cDNA from a mouse s train expressing the neomycin resistance gene demonstrated that this p rocedure is capable of identifying species present in one population b ut absent from another. Furthermore, experiments to identify genes wit h circadian expression patterns in mouse liver demonstrated that SABRE is capable of detecting even modest 2- to 10-fold differences in accu mulation of moderately rare mRNA species, representing as little as 0. 03% of total mRNA. These experiments identified the gene encoding coum arin 7-hydroxylase as displaying circadian expression in mouse liver.