In the Cyp40KO allele, the stop codon should be introduced after the 564th nucleotide of the Cyp40 CDS. Thus, the stop codon should make a truncated Cyp40 polypeptide (1-188), as below. But, the truncated protein was undetectable by immunoblotting, and may need further validation. We confirmed that the Cyp40 transcript is lost in this mutant, and the sperm phenotype is recovered by the Cyp40 transgene. Hence, the allele is considered to be Cyp40KO. In addition, the transcriptome of Cyp40-/- (KODF) is showing that the mRNA is expectedly truncated in the middle (unpublished). The home-made polyclonal anti-Cyp40 antibody confirmed the absence of intact Cyp40 proetin in Cyp40-/- testes (published).
