St3gal1^tm1Jxm

Exon 2 was flanked by loxP sites and a loxP-tk-neo cassette was inserted into the upstream intron via homologous recombination. Transient expression of cre recominase in correctly targeted cells facilitated the removal of exon 2 and the loxP-tk-neo cassette resulting in deletion of the sialyl motif essential for catalysis. (J:79167)