Fig. 4.

Pof8 is important for maintaining cellular levels of TER1 RNA. a Elimination of Pof8 leads to ~4.3-fold reduction in cellular telomerase RNA level. b Expression level of TER1 precursor RNA, still carrying an intron near the 3′ end of RNA, was not reduced in pof8∆ cells. For a and b, TER1 RNA expression levels were normalized to his1⁺ mRNA expression. c TER1-Lsm3 interaction was eliminated in pof8∆. The plot shows fold enrichment of TER1 RNA recovered after IP compared to no tag control strain. d, e Examination of (d) Lsm3-Pof8 and (e) Lsm3-Trt1 interactions by co-IP. Trt1 band marked with asterisk (*) in myc-IP blot corresponds to previously reported⁷⁰ higher molecular weight band. f Quantitative real-time PCR ChIP assays showed that telomere association of Lsm3 is independent of Pof8 or the telomerase subunits TER1, Trt1, and Est1. Unexpectedly, Lsm3 binding was increased when telomerase RNA was eliminated. Expression levels of myc-tagged Lsm3 used in ChIP assays were monitored by western blot analysis. Anti-Cdc2 blots served as loading control. Molecular weight (kDa) of size markers are also indicated. Error bars for plots in a through c and f correspond to SEM from at least 6 independent experiments. Raw data and statistical analysis are available in Supplementary Data 1. g A model of fission yeast telomerase holoenzyme complex based on current and previous co-IP data