This allele was generated from Sema3atm1Tyag by transient cre expression in TT-2 cells. Recombination produced three alleles, Sema3atm1.1Tyag, Sema3atm1.2Tyag and Sema3atm1.3Tyag. Sema3atm1.2 has loxP sites inserted before and after the first exon. (J:43443)