Esr1-KO mice (Stock No.NM-KO-190631) carry a knockout allele derived from the targeted deletion of exon 3. While Esr1-KO(2) mice (Stock No.NM-KO-200651) carrying the exon 4 deletion.Esr1-KO(3) mice (Stock No.210243) carrying the exon 4 deletion. (J:238766)