Updated project metadata.
Super killer (SKI) complex is a well-known cytoplasmic 3′ to 5′ mRNA decay complex that functions with the exosome to degrade excessive and aberrant mRNAs. Recently, SKIV2L, the 3′ to 5′ RNA helicase of the human SKI (hSKI) complex has been implicated with the extraction of mRNA at stalled ribosomes, tackling aberrant translation. Here, we show that SKIV2L and TTC37 of the hSKI complex are present within the nucleus, localise on chromatin and at some telomeres during the G2 cell cycle phase. In cells, SKIV2L prevents telomere replication stress shown as fragile telomeres and increases the stability of telomere DNA-RNA hybrids in G2 of the cell cycle whereas its absence decreases the amount of those structures. We further demonstrate that purified hSKI complex binds telomeric DNA and RNA substrates in vitro. Moreover, SKIV2L association with telomeres is dependent on DNA-RNA hybrids but its helicase activity is dispensable for its telomeric function. Taken together, our results provide a nuclear function for SKIV2L of the hSKI complex in overcoming replication stress at telomeres mediated by its recruitment to DNA-RNA hybrid structures in G2 and thus maintaining telomere stability.