Acta Veterinaria et Zootechnica Sinica ›› 2023, Vol. 54 ›› Issue (6): 2330-2342.doi: 10.11843/j.issn.0366-6964.2023.06.013

• ANIMAL GENETICS AND BREEDING • Previous Articles     Next Articles

PhiC31 Integrase Triggers Site-specific Cassette Exchange in Chicken Fibroblast Cells through Electroporation

WANG Hui, XU Mengyuan, LIU Lingkang, ZHENG Xibang*, LI Gonghe, WU Wende   

  1. College of Animal Science and Technology, Guangxi University, Nanning 530004, China
  • Received:2023-01-06 Online:2023-06-23 Published:2023-06-16

Abstract: The present study aimed to evaluate whether the direct protein delivery of PhiC31 integrase through electroporation could induce the PhiC31-mediated recombination in chicken DF-1 cells. Here, prokaryotic expression and affinity chromatography purification was used to produce a small ubiquitin-related modifier (SUMO)-tagged His-PhiC31 fusion protein, and a SUMO proteinase was utilized to generate a natural PhiC31 protein by removing SUMO-His tag. The two types of PhiC31 protein were respectively incubated with pBCPB+ plasmid in tubes to induce intermolecular recombination. Subsequently, a landing pad (LP) plasmid harboring the attPTT-DsRed2-attPCT fragment was electroporated into the chicken DF-1 cells, followed by another round of electroporation of the natural PhiC31 protein along with a donor plasmid carrying the attBTT-EGFP-HiBiT-attBCT segment. The results showed that a prokaryotic expression vector (pET-28a-SUMO-PhiC31) was successfully constructed, and SUMO-His-PhiC31 fusion protein was expressed in a resolvable pattern in E.coli with induction of isopropyl-β-D-thiogalactoside (IPTG), and amount of the purified fusion protein reached 12 mg·L-1; both SUMO-His-PhiC31 and natural SUMO-free PhiC31 were capable of triggering the intermolecular recombination between attP and attB sites of pBCPB+ plasmid, and the recombinant efficiency of SUMO-His-PhiC31 was comparable to that of PhiC31 proteins (50% vs. 52%); co-transfection of DF-1 cells with a PhiC31 expressing vector pCMVInt, LP and donor plasmids resulted in conversion of DsRed2 to EGFP, which was confirmed by fluorescent microscopy; the same results were observed when LP plasmid, the donor plasmid plus PhiC31 protein were successively electroporated to DF-1 cells, implying the occur of PhiC31-mediated recombination between attPTT and attBTT, attPCT and attBCT, respectively. The results indicated that the natural PhiC31 protein is biologically active. The protein is expected to serve as an important reagent in the Easi-CRISPR-TARGATT-mediated genome editing to generate transgenic chickens.

Key words: PhiC31 integrase, prokaryotic expression, electroporation, recombinase mediated cassette exchange (RMCE), DF-1 cells, chicken

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