PRPF19 mRNA Encodes a Small Open Reading Frame That Is Important for Viability of Human Cells.

High-throughput ribosome profiling demonstrates the translation of thousands of small open reading frames located in the 5' untranslated regions of messenger RNAs (upstream ORFs). Upstream ORF can both perform a regulatory function by influencing the translation of the downstream main ORF and encode a small functional protein or microprotein. In this work, we showed that the 5' untranslated region of the PRPF19 mRNA encodes an upstream ORF that is translated in human cells. Inactivation of this upstream ORF reduces the viability of human cells.