A telomerase holoenzyme protein enhances telomerase RNA assembly with telomerase reverse transcriptase.
Telomerase maintains the simple sequence repeats at chromosome ends, protecting cells from genomic rearrangement, proliferative senescence and death. The telomerase reverse transcriptase (TERT) and telomerase RNA (TER) alone can assemble into active enzyme in a heterologous cell extract, but the physiological process of telomerase biogenesis is more complex. The endogenous accumulation of Tetrahymena thermophila TERT and TER requires an additional telomerase holoenzyme protein, p65. Here, we reconstitute this cellular pathway for telomerase ribonucleoprotein biogenesis in vitro. We demonstrate that tandem RNA interaction domains in p65 recognize the sequence of the TER 3' stem. Notably, the p65-TER complex recruits TERT much more efficiently than does TER alone. Using bacterially expressed p65 and TERT polypeptides, we show that p65 enhances TERT-TER interaction by a mechanism involving a conserved bulge in the protein-bridging TER molecule. These findings reveal a pathway for telomerase holoenzyme biogenesis that preassembles TER for TERT recruitment.
Prathapam
Ramadevi
R
Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
Witkin
Keren L
KL
O'Connor
Catherine M
CM
Collins
Kathleen
K
D000818:Animals; D001483:Base Sequence; D004268:DNA-Binding Proteins; D020035:Holoenzymes / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology*; D009690:Nucleic Acid Conformation; D010750:Phosphoproteins / Q000378:metabolism / Q000502:physiology*; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary / Q000502:physiology; D015800:Protozoan Proteins / Q000378:metabolism / Q000502:physiology*; D012313:RNA / Q000378:metabolism*; D019098:Telomerase / Q000378:metabolism*; D016808:Tetrahymena thermophila / Q000201:enzymology / Q000378:metabolism
D004268:DNA-Binding Proteins; D020035:Holoenzymes; D009687:Nuclear Proteins; C101880:Pdd1 protein, Tetrahymena; D010750:Phosphoproteins; D015800:Protozoan Proteins; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase