• BMB Reports
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• v.34 no.4
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• pp.322-328
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• 2001

Excision and amplification of pre-determined, large genomic segments (taken directly from the genome of a natural host, which provides an alternative to conventional cloning in foreign vectors and hosts) was explored in human cells. In this approach, we devised a procedure for excising a large segment of human genomic DNA, the iNOS gene, by using the Cre/loxP system of bacteriophage P1 and amplifying the excised circles with the EBNA-1/oriP system of the Epstein-Barr virus. Two loxP sequences, each of which serves as a recognition site for recombinase Cre, were integrated unidirectionally into the 5'-UTR and 3'-UTR regions of the iNOS gene, together with an oriP sequence for conditional replication. The traps-acting genes cre and EBNA-1, which were under the control of a tetracycline responsive $P_{hcmv^*-1}$ promoter, were also inserted into the 5'-UTR and 3'-UTR regions of the iNOS gene, respectively, by homologous recombination. The strain carrying the inserted elements was stably maintained until the excision and amplification functions were triggered by the induction of cre and EBNA-1. Upon induction by doxycycline, Cre excised the iNOS gene that was flanked by two ZoxP sites and circularized it. The circularized iNOS gene was then amplified by the EBNA-1/oriP-system. With this procedure, approximately a 45.8-kb iNOS genomic fragment of human chromosome 17 was excised and successfully amplified in human cells. Our procedure can be used effectively for the sequencing of unclonable genes, the functional analysis of unknown genes, and gene therapy.

• International Journal of Stem Cells
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• v.16 no.1
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• pp.36-43
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• 2023

Background and Objectives: Lymphoblastoid cell lines (LCLs) deposited from disease-affected individuals could be a valuable donor cell source for generating disease-specific induced pluripotent stem cells (iPSCs). However, generation of iPSCs from the LCLs is still challenging, as yet no effective gene delivery strategy has been developed. Methods and Results: Here, we reveal an effective gene delivery method specifically for LCLs. We found that LCLs appear to be refractory toward retroviral and lentiviral transduction. Consequently, lentiviral and retroviral transduction of OCT4, SOX2, KFL4 and c-MYC into LCLs does not elicit iPSC colony formation. Interestingly, however we found that transfection of oriP/EBNA-1-based episomal vectors by electroporation is an efficient gene delivery system into LCLs, enabling iPSC generation from LCLs. These iPSCs expressed pluripotency makers (OCT4, NANOG, SSEA4, SALL4) and could form embryoid bodies. Conclusions: Our data show that electroporation is an effective gene delivery method with which LCLs can be efficiently reprogrammed into iPSCs.