The second line, designated as BptfΔExon2, was generated by targeting loxP sites flanking exon 2 of Bptf (Figure S2A, Figure S2G, Figure S2H, Figure S2I, Figure S2J, Figure S2K, Figure S2L, Figure S2M, Figure S2N). The expression of the BptfΔExon2 allele was assessed by RT-PCR with the use of primer sets which amplify sequences on the 3′ end of the Bptf transcript. We found that the BptfΔExon2 allele slightly decreases expression of Bptf at the RNA level (Figure S4A). However, amplification and sequencing of the BptfΔExon2 mRNA from exons 1 to 8 shows an out-of-frame mutant mRNA, indicating that BptfΔExon2 behaves as a loss-of-function allele (Figure S4B, Figure S4C).
