PCR products are frequently cloned into plasmid vectors for subsequent manipulations, such as sequencing and mutagenesis. The pGEM®-T Vector Systems, and other T-vectors available from Promega, allow direct cloning of PCR products without restriction digestion, modification of primers or purification of amplified DNA. The thymidine overhangs of the pGEM®-T Vectors are stable even when the DNA is subjected to freezing and heating.
Promega Notes 65, 25.