The relative expression of TERC was measured by RT-qPCR from total RNA of HeLaS3 and AGO2KO cells. HPRT1 was used as internal control (n = 3 experimental replicates). qPCR of 3'-extended TERC transcript in cDNA from HeLaS3 and AGO2KO cells generated using random hexamers. HPRT1 was used for normalization (n=3 experimental replicates). qPCR of TERC transcript in cDNA from HeLaS3 and AGO2KO cells generated using oligo(dT)10 priming. HPRT1 was used for normalization (n=3 experimental replicates). 