An RNA dependent RNA polymerase formed by hTERT and the RNase MRP RNA

Constitutive expression of telomerase in human cells prevents the onset of senescence and crisis by maintaining telomere homeostasis. However, accumulating evidence suggests that the human telomerase catalytic subunit (hTERT) contributes to cell physiology independent of its ability to elongate telomeres. Here we show that hTERT interacts with the RNA component of mitochondrial RNA processing endoribonuclease (RMRP), a gene that is mutated in the inherited pleiotropic syndrome Cartilage-Hair Hypoplasia. hTERT and RMRP form a distinct ribonucleoprotein complex that exhibits RNA dependent RNA polymerase (RdRP) activity and produces double-stranded RNAs that can be processed into small interfering RNA in a Dicer-dependent manner. These observations identify a mammalian RdRP composed of hTERT in complex with RMRP.