Roles for RNA in telomerase nucleotide and repeat addition processivity.
Telomerase is a ribonucleoprotein reverse transcriptase with two subunits critical for catalytic activity, the protein telomerase reverse transcriptase (TERT) and telomerase RNA. In this study, we establish additional roles of the telomerase RNA subunit by demonstrating that RNA motifs stimulate the processivity of nucleotide and repeat addition. These functions are both functionally and physically separable from the roles of other RNA motifs in establishing a properly defined template. Binding of Tetrahymena telomerase RNA stem IV to TERT enhances nucleotide addition processivity, while a cooperation of the RNA pseudoknot and stem IV promotes repeat addition processivity. The low processivity of DNA synthesis by telomerase ribonucleoproteins lacking the pseudoknot and/or stem IV can be rescued by addition of the deleted region in trans. These findings demonstrate RNA elements with roles in telomerase elongation processivity that are distinct from RNA elements that specify the internal template.
Lai
Cary K
CK
Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA 94720, USA.
Miller
Michael C
MC
Collins
Kathleen
K
D020816:Amino Acid Motifs; D000818:Animals; D020029:Base Pairing; D004268:DNA-Binding Proteins; D019143:Evolution, Molecular; D008954:Models, Biological; D009711:Nucleotides / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D019098:Telomerase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013698:Templates, Genetic; D013768:Tetrahymena / Q000201:enzymology*
D004268:DNA-Binding Proteins; D009711:Nucleotides; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D011994:Recombinant Proteins; D019098:Telomerase