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. Sema3tm1.1Tyag has had the first exon, including the initiation codon, deleted. (J:43443)