cDNA of the 412-amino acid 4-repeat isoform of the human MAPT gene was reamplified and modified by PCR-based site directed mutagenesis to introduce a Kozak-sequence and the mutations G272V and P301S (numbering according to longest human isoform). The cDNA was inserted into a Thy1.2 expression vector and the construct was microinjected into a C57BL/6 x CBA background. 10 copies of the transgene are detected in line 22 animals. Western blot analysis shows high levels of MAPT expression in the brains, and low levels in the spinal cords, of transgenic animals from line 22.