A putative cap binding protein and the methyl phosphate capping enzyme Bin3/MePCE function with the Larp7 family member Pof8 in the biogenesis of telomerase

We have identified two previously uncharacterized proteins involved in telomerase biogenesis. Both proteins are required for telomerase activity and telomere length maintenance. We named these proteins Thc1 (Telomerase Holoenzyme Component 1) and Bmc1 (Bin3/MePCE 1) based on structural and sequence similarities to the nuclear cap binding complex and the methyl phosphate capping enzyme (Bin3/MePCE) in metazoans, respectively. Thc1 and Bmc1 function together with Pof8 in recognizing telomerase RNA and promoting the recruitment of the Lsm2-8 complex and the catalytic subunit to assemble functional telomerase. Identification of undescribed fission yeast telomerase subunits by using Pof8, a telomerase constitutive member, as bait.