INVERTED TERMINAL REPEATS PERMIT THE AVERAGE LENGTH OF AMPLIFIED DNA FRAGMENTS TO BE REGULATED DURING PREPARATION OF CDNA LIBRARIES BY POLYMERASE CHAIN-REACTION

A simple polymerase chain reaction (PCR)-based technique for construct ion of cDNA libraries starting with very small amounts of cells or tis sues is described. The technique is based on the insertion of inverted terminal repeats into amplified cDNAs which permit short molecules to generate ''pan''-type structures at each cycle of PCR amplification a nd thus to escape annealing with primers. This allows one to avoid amp lification of primer dimers and makes it possible to perform oligonucl eotide tailing of the first cDNA strands followed by PCR amplification in the same tube. Moreover, the average size of amplified cDNAs can b e controlled by varying the primer concentration. (C) 1995 Academic Pr ess, Inc.