Zbtb7b^tm2Itan

ES cells containing the GFP knock-in allele, Zbtb7btm1Tani, were targeted for a second mutation. A loxP site was placed approximately 6 kb upstream of the transcription start site, placing it 5' to a proximal enhancer for this gene locus. A floxed neo-cassette was placed downstream of the enhancer. Transient expression of cre-recombinase removed a 2.2-kb region including the proximal enhancer and the neo cassette. Southern blotting confirmed correct targeting of the knock in allele. (J:141142)