Fig. 1

Schematic outlining the binding of Snord115 to Htr2c and how alternate splicing can lead to full-length and truncated 5HT_2CRs. Binding of Snord115 to a specific sequence in exon Va of the Htr2c pre-RNA promotes the inclusion of exon Vb and the production of the full-length 5HT_2CR; the exon/alternative exon border in the proximal splice site (GG) is underlined. Skipping of exon Vb leads to the introduction of a premature “stop” codon and the production of a truncated 5HT_2CR isoform. Loss of snord115 expression, as is expected in the majority of cases of PWS, is expected to lead to an increase in levels of the truncated 5HT_2CR isoform