Fig. 1

Four Prdm9 deletions generated in SHR rats lead to mRNAs with open reading frame truncations and one also to alternative mRNA with deletion of 20 codons. a mRNAs arising from rats with genomic deletions of 2-, 8-, 39-, and 516-bp (abbreviated KO2, KO8, KO39, and KO516, respectively; the latter two also involve a part of Intron 8); blue dashes, gaps to optimize the alignment; red dashes, exonic deletions; -U, -L, two new mRNAs from the animal with the KO516 deletion. b Polypeptide products predicted from mRNAs in a and their detection. -20 a.a., deletion of 20 amino acid residues. The C-terminal boxes indicate zinc-fingers and the three letters their DNA-binding amino acids. See Additional file 1: Fig. S1 for details of the translations and amino acids essential for methyltransferase activity and Additional file 2: Table S1 for genomic and cDNA sequences. Right, PRDM9 was detected at the expected sizes of 97 kDa (mouse Dom2 allele) and 96 kDa (rat SHR allele). Anti-SYCP3 antibody was utilized as a loading control. PRDM9 was present in the SHR-Prdm9^KO516/KO516 mutants at the expected size of the KO516-L isoform (91 kDa), but its expression was lower than that of the wild-type in SHR; the KO516-U isoform (predicted 40 kDa) was undetectable. KO39 mutant product was not found (expected 44 kDa) in the SHR-Prdm9^KO39/KO39 testes, thus no C-terminally truncated form of PRDM9 was seen in either mutant. Only a third of the amount of protein nuclear extract was loaded in mouse (10 μg) compared to rat (30 μg) lanes