BAC clone RP23-223G1 containing the mouse Fut1, Fut2, and Sec1 loci was manipulated through Red/ET recombination technology. In this deletion, a loxP-flanked neomycin cassette is used to replace a 30 kB region containing the coding region of Fut2 and Sec1. The BAC was also modified to contain a knockout of Fut1, Fut1tm1Dzhou (J:278494)