Effective generation of transgenic mice by Bovine papillomavirus type 1 based self-replicating plasmid that is maintained as extrachromosomal genetic element in three generations of animals

Abstract

The objective of our study was to analyze the efficiency and the properties of the inheritance of the Bovine papillomavirus type 1 (BPV1) replicator-based plasmid used as vector system for generation of transgenic animals. Previously, we have characterized a series of self-replicating plasmid vectors containing all viral factors necessary and sufficient for stable extrachromosomal replication of the BPV1 genome in the tissue culture system. We also demonstrated that the designed replicating vector system has a considerable benefit in the transgene expression, if compared to the regular expression vector. The vector, which showed the highest stability and maintenance function in the tissue culture was chosen for generation of the transgenic mice by pronuclear injections of the circular supercoiled plasmid. This method resulted in successful production of transgenic animals. Transmission efficiency of the vectors into the F 1 generation of animals varied between 0 and 48%, whereas transmission into the F 2 generation was uniformly near 50%. The maintenance of the vector-plasmids in the F 2 generation of transgenic animals as extrachromosomal genetic element was demonstrated by rescue of the plasmid into the Escherichia coli.