The invention relates to an
allele double knockout targeting
vector system and a construction method thereof. The
system of the invention consists of two complementary vectors, namely pGT-V1 and pGT-V2, wherein each vector contains two in phase LoxP elements which contain a
positive selection marker gene Neo / GFP and Hyg / RFP respectively; and the outside of each vector contains a
negative selection marker gene TK. Meanwhile, two 8-basic group multiple
cloning sites are designed and arranged between the two LoxP elements and the
negative selection marker for the
insertion of the homology arm. By adopting the constructed targeting
vector system of the invention, two complementary targeting vectors are cotransfected into the recipient
cell; through the selection of
drug and fluorescent double-selection marker, the genetic modification or knockout of the two alleles of the
target gene can be realized once; and the interaction of the transfected Cre
enzyme and the LoxP elements can be utilized to remove the selection
marker gene integrated with the
genome, the time of obtaining the homozygous knockout target
cell can be shortened, the safety of the transgenic animal can be increased and a valuable technology platform is provided to develop the animal transgenic researches.