The recent discovery of numerous human short open reading frame (sORF)-encoded polypeptides (SEPs) has raised important questions about the functional roles of these molecules in cells. Here, we show that a 69-amino acid SEP, MRI-2, physically interacts with the Ku heterodimer to stimulate DNA double-strand break ligation via nonhomologous end joining. The characterization of MRI-2 suggests that this SEP may participate in DNA repair and underscores the potential of SEPs to serve important biological functions in mammalian cells.
The recent discovery of numerous human short open reading frame (sORF)-encoded polypeptides (SEPs) has raised important questions about the functional roles of these molecules in cells. Here, we show that a 69-amino acid SEP, MRI-2, physically interacts with the Ku heterodimer to stimulate DNA double-strand break ligation via nonhomologous end joining. The characterization of MRI-2 suggests that this SEP may participate in DNA repair and underscores the potential of SEPs to serve important biological functions in mammalian cells.
