Rr149356^tm1.1Pf

The 560-bp HpaINcoI restriction fragment containing Tcrb enhancer Ebeta was replaced with a loxP site flanked neomycin resistance gene cassette. The neo cassette was removed through subsequent cre-mediated recombination. Mutants were shown to lack Tcrb rearrangement by DNA-PCR and RNA-PCR analyses although germ-line Vbeta transcripts were detectable at a low level. (J:34311)