Fig. 4.
The interplay between the authentic and the cryptic 5′ss governs the pathogenic effect of natural OTC mutations. A Schematic representation of the human OTC exon 4 genomic sequence cloned as minigene in the pTB vector within the NdeI sites. Exonic and intronic sequences are represented by boxes and lines, respectively. Primers (arrows) used to perform the RT-PCR are indicated on top. The sequences, with exonic and intronic nucleotides in upper and lower cases respectively, report (i) the authentic 5′ss with the positions of the investigated changes detailed below, and (ii) the cryptic 5′ss. Both 5′ss are underlined. The table reports the scores of the 5′ss in the normal sequence and in the presence of different OTC nucleotide changes found in OTCD patients. B OTCh splicing patterns evaluated by RT-PCR and denaturing capillary electrophoresis on RNA isolated from HepG2 transiently transfected with the wild-type (wt) minigene or harboring the indicated nucleotide changes. The schematic representation of transcripts (with exons not in scale) is reported on top. Numbers on the right report the relative percentage of each transcript type