This transgene is a hybrid Thy1 gene in which a 0.8 kb BstEII-ApaI fragment containing part of exons 3 and 4 of the mouse gene was replaced with the homologous 0.96 kb BstEII-ApaI human THY1 gene fragment (containing the mature protein and transmembrane sequences) while the 5' and 3' flanking regions are mouse sequences. High expression of the hybrid transgene is seen in the kidney proximal tubular epithelium and in the brain.