Figure 2. Crossing Arf ^fl/fl mice with CtsK^Cre/+ mice results in germline Arf loss.

(A) Three sets of primer pairs were designed to detect the presence of floxed exon 1beta, which is unique to Arf. (B) PCR products were not detected upon genotyping new mice for the presence of the 5′ loxP site (far left panel). This cannot be attributed to an absence of DNA (middle left panel). Controls are mice that were never crossed with Ctsk^Cre/+ mice. Two sets of primer pairs were used to detect the presence of exon 1beta. Each set detects a product indicating loss of exon 1beta (product size labeled as “KO” in table). (C) Immunofluorescent staining for ARF in testis tissues indicates the loss of exon 1beta at the protein level (scale bar = 100 µM).