Myt1^tm1Ggu

A FRT flanked pGK-Neo cassette and a loxP site was inserted upstream of exon 9 (or exon 3 when the short alternative transcript is being produced) and a third loxP site was inserted downstream of the exon. Mice were crossed with a Flpe deleter strain to remove the selection cassette, leaving the targeted exon flanked by loxP sites with one FRT site remaining upstream of the targeted exon but downstream of the first loxP site. (J:127471)