Roles of SNORD115 and SNORD116 ncRNA clusters during neuronal differentiation

In the snoRNA host gene SNHG14, 29 consecutive introns each generate SNORD116, and 48 tandem introns encode SNORD115. Loss of SNORD116 expression, but not of SNORD115, is linked to the neurodevelopmental disease Prader-Willi syndrome. SNORD116 and SNORD115 resemble box C/D small nucleolar RNAs (snoRNAs) but lack known targets. Both were strongly accumulated during neuronal differentiation, but with distinct mechanisms: Increased host-gene expression for SNORD115 and apparent stabilization for SNORD116. For functional characterization we created cell lines specifically lacking the expressed, paternally inherited, SNORD115 or SNORD116 cluster. Analyses during neuronal development indicated changes in RNA stability and protein synthesis. These data suggested that the loss of SNORD116 enhanced some aspects of developmental timing of neuronal cells. Depleted mRNAs included MAGEL2, causal in the PWS-like disorder Schaaf-Yang syndrome. Comparison of SNORD115 and SNORD116 mutants identified small numbers of altered mRNAs and ncRNAs. These were enriched for functions potentially linked to PWS phenotypes. Overall design: To inversigate the role of non-coding RNAs from SNORD116 and SNORD115 clusters, we created cell lines with heterozygous deletions in paternal chromosome in LUHMES, neuronal progenitor cells and performed RNAseq analysis during the differentiation to dopaminergic neurons at day 0, 6, 10 and 15.