Strategy for Construction of a cDNA Encoding a Repetitive Amino Acid Sequence

The polymerase chain reaction (PCR) is a powerful method permitting generation of almost any desired cDNA sequence. Construction of cDNA fragments that encode repetitive amino acid sequences by PCR has proven problematic, however, as repetitive nucleotide primers tend to amplify undesired fragments (because of their misannealing with the template). To overcome this problem, Dombrowski and Wright (1 ) developed a solid-phase gene-assembly protocol, but because this technique requires preparation of a solid-phase reaction system, it cannot be routinely performed in most laboratories. Here, we describe a new strategy that makes use of standard PCR protocols, yet enables assembly of cDNAs encoding repetitive amino acid sequences (2 ).