Identification of a Specific Pseudo attP Site for Phage phiC3 Integrase in the Genome of Chinese Hamster in CHO-K1 Cell Line

PhiC31 integrase is a DNA site-specific recombinase integrates DNA into the chromosomes between the two sites of attB and attP. Several pseudo attPs have been identified in mammalian genomes with critical features for long-term expression of transgene. In this manuscript, we report a novel intrinsic pseudo attP site named CHOL1 in the Chinese hamster genome implementing an inverse Polymerase Chain Reaction (IPCR).. Identification of pseudo attP site(s) of Tenecteplase cDNA integration in the genome of stable transformed CHO cell line.. First, genome was extracted from a stable transformed CHO cell line expressing Tenecteplase. By creating of minicircle DNA in the last step, sequencing was performed.. We obtained one band. BLAST analysis of the respective sequence of inverse PCR band identified a pseudo attP site.. Data demonstrated that the phiC31 integrase provides a suitable insertion site in the genome to express the gene of interest..