Efficient generation of transgenic BALB/c mice using BALB/c embryonic stemcells

BALB/c is one of the most widely used and best characterized mouse strains in immunology. For various applications, it is necessary to generate BALB/c transgenic mice. However, using the conventional microinjection technique it is extremely inefficient to produce transgenic BALB/c mice since the one -cell stage BALB/c embryos are highly vulnerable to pronuclear DNA microinj ection. To overcome this problem, we have investigated the generation of Eg r-1 (early growth response gene) transgenic mice via the transfection of BA LB/c embryonic stem cells. Transfectants carrying Egr-1 constructs comprisi ng either the immunoglobulin heavy chain or the MHC class II promoter/enhan cer system were injected into C57BL/6 host blastocysts resulting in chimeri c mice. For both type of expression vectors, transgenic offspring of the ge rmline chimeras expressed recombinant Egr-1 in lymphoid tissues containing B cells. This demonstrates the successful generation of Egr-1 transgenic BA LB/c mice using transfected ES cell. (C) 1999 Elsevier Science B.V. All rig hts reserved.