Intracellular trafficking of yeast telomerase components.
Telomerase uses an internal RNA moiety as template for the synthesis of telomere repeats. In Saccharomyces cerevisiae, the telomerase holoenzyme contains the telomerase reverse transcriptase subunit Est2p, the telomerase RNA moiety TLC1, the telomerase associated proteins Est1p and Est3p, and Sm proteins. Here we assess telomerase assembly by determining the localization of telomerase components. We found that Est1p, Est2p and TLC1 can migrate independently of each other to the nucleus. With limiting amounts of TLC1, overexpressed Est1p and Est2p accumulated in the nucleolus, whereas enzymatically active Est2p-TLC1 complexes are distributed over the entire nucleus. The distribution to the nucleoplasm depended on the specific interaction between Est2p and TLC1 but was independent of Est1p and Est3p. Altogether, our results suggest a role of the nucleolus in telomerase biogenesis. We also describe experiments that support a transient cytoplasmic localization of TLC1 RNA.
Teixeira
M Teresa
MT
Swiss Institute for Experimental Cancer Research (ISREC), Epalinges, Switzerland.
Forstemann
Klaus
K
Gasser
Susan M
SM
Lingner
Joachim
J
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D020134:Catalytic Domain; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D007150:Immunohistochemistry; D046911:Macromolecular Substances; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D016366:Open Reading Frames; D011506:Proteins / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020718:Ribonucleoproteins, Small Nucleolar / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; C064793:NOP1 protein, S cerevisiae; D009687:Nuclear Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; D020718:Ribonucleoproteins, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; C099024:EST1 protein, S cerevisiae; C491580:EST3 protein, S cerevisiae; D019098:Telomerase