Extended Data Figure 2. Generation of a chromosome 11B3 conditional knockout mouse.

a, Top, strategy to introduce 5′ HPRT gene and loxP site telomeric to Sco1 on chromosome 11B3 with MICER clone MHPN91j22. Bottom, Southern blot demonstrating correct targeting of the derived ES cells. st, single-targeted allele; wt, wild-type. Blue arrowheads denote loxP sites. b, Top, strategy to introduce 3′ HPRT gene and loxP site centromeric to Alox12 on chromosome 11B3 with MICER clone MHPP248j19. Bottom, Southern blot demonstrating correct targeting of the derived ES cells. dt, double-targeted allele. c, Top, diagram showing the expected PCR results and drug-resistance phenotypes of doubly targeted ES cells harbouring loxP sites in cis versus in trans. G^r, G418 (neomycin) resistance; P^r, puromycin resistance; H^r, HAT resistance. df, deleted allele; dp, duplicated allele. Green bar indicates the PCR product location and length. Bottom, PCR results show different ES cell clones generated in a and b.