Tcrb^tm1(Tcrb)Chb

ES cells homozygous for the Tcrbtm1Slek allele that lacks the Dbeta2-Jbeta2 was targeted a second time. A preassembled Dbeta1Jbeta1.1 complex, which did not contain N or P nucleotides and was missing just one C nucleotide compared with the genomic sequence, replaced the germline Dbeta1 and Jbeta1.1 segments. A floxed neomycin resistance gene and a HindIII restriction site were inserted between the Jbeta1.2 and Jbeta1.3 segments. Transient expression of cre recombinase removed the neomycin cassette while leaving behind the HindIII site and a loxP site. The novel HindIII site helped distinguish between Tcrb rearrangements on this allele versus the Tcrbtm1Slek allele. (J:147947)