Fig. 1
From: Generation of a novel mouse model of nemaline myopathy due to recurrent NEB exon 55 deletion
Pseudoexon identification and Hmz-NebΔExon55 model generation. (A) RNAseq Sashimi plots from n = 2 NebΔExon55 mice compared to a WT control spanning Neb exons 54–56. Numbers with connecting arches indicate splice junction reads, which are a measure of the number of transcripts from the indicated spliced products. With exon 55 deletion, it would be predicted that exon 54 is spliced directed to 56; however, in the NebΔExon55 mice, ~ 94% of the transcript includes intronic material between exons 54 and 56, with distinct splice donor and acceptor sites forming a pseudoexon. (B) Cartoon depiction of NebΔExon55 pseudoexon depicting the location of cryptic splice sites leading to the pseudoexon being spliced into the mature mRNA. Translated amino acid sequence of the pseudoexon contains two premature termination codons (PTC). The presence of these PTCs likely leads to transcript degradation through nonsense mediated decay (NMD), explaining the reduced Neb transcript levels in the NebΔExon55 mice. (C) Schematic of Hmz-NebΔExon55 model development whereby 380 bp of sequence encompassing the pseudoexon is replaced with a short 58 bp human intron 54 sequence containing a validated cas9 gRNA protospacer sequence. The resulting allele has a slightly shorter intronic sequence than the original and no longer contains the pseudoexon sequence that was being spliced in.