Cloning cDNA Ends Using RACE

Most attempts to identify and isolate a novel cDNA result in the acquisition of clones that represent only a part of the mRNA’s complete sequence. The approach described here to clone the missing sequence (cDNA ends) employs polymerase chain reaction (PCR). Since the initial reports of rapid amplification of cDNA ends (RACE) (1 ) or related techniques (2 ,3 ), many labs have developed significant improvements on the basic approach (5 –18 ). The most recent hybrid version of the relatively simple classic RACE is described here, as well as a more powerful but technically more challenging “New RACE” protocol which is adapted from the work of a number of laboratories (19 –26 ). Commercial RACE kits are available from Bethesda Research Labortories (BRL; Gaithersburg, MD) (11 ) and Clontech (Palo Alto, CA) that are convenient but not as powerful as the most recent versions of Classic and New RACE.