Is it possible to secrete a protein with an amino-terminal antibody epitope tag?
Yes. An adaptation of Cloning Strategy I in the K. lactis Protein Expression Kit manual can be used. In this strategy, a new forward PCR primer is used that contains (5’ to 3’): an Xho I restriction site, codons encoding the Kex protease cleavage site (KR) immediately followed by DNA encoding the desired tag’s sequence and DNA homologous to the 5’ end of the desired gene or cDNA. The reverse primer is designed as described in Cloning Strategy I and the amplified product is cloned into pKLAC1. After Kex protease processing of the expressed protein in the Golgi, a protein bearing the desired tag at its amino-terminus is produced and secreted.
