Cre-mediated recombination removed floxed exons 12 and 14 of L1camtm1Vlem, leaving a neo cassette in intron 14. These exons encode the sixth Ig domain. Protein expression levels were similar in mutant and wild-type lymphocytes, as demonstrated by Western blot, and flow cytometry confirmed the loss of expression of the sixth Ig domain epitope. (J:89300)