title: The Tetrahymena p80/p95 complex is required for proper telomere length maintenance and micronuclear genome stability.
abstract: The telomerase enzyme adds simple sequence repeats to chromosome ends. Telomerases share two essential subunits, telomerase RNA and telomerase reverse transcriptase, that associate with species-specific proteins of predominantly unknown functions. The Tetrahymena p80/p95 complex can coimmunopurify active telomerase from cell extract, and recombinant p80/p95 can interact directly with telomerase RNA and single-stranded telomeric DNA in vitro. Here, we test the functions of p80/p95 in vivo. Surprisingly, telomerase RNA accumulation and telomerase activity in cell extract are unaffected by loss of the genes encoding p80/p95. However, in the absence of p80/p95, telomeres become elongated in both macronuclei and micronuclei. Micronuclear chromosome maintenance is also compromised. These findings suggest that p80/p95 functions to maintain appropriate telomere length and micronuclear genomic stability but does so in a manner different than previously anticipated.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Miller
authors.forename: K
authors.initials: K
authors.lastname: Collins
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D018503:Genome, Protozoan; D048631:Micronucleus, Germline / Q000235:genetics*; D010641:Phenotype; D021122:Protein Subunits; D015800:Protozoan Proteins / Q000378:metabolism*; D016053:RNA, Protozoan / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D019098:Telomerase / Q000378:metabolism*; D016615:Telomere / Q000235:genetics*; D034501:Telomere-Binding Proteins; D013768:Tetrahymena / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D014170:Transformation, Genetic
chemical_list: D002352:Carrier Proteins; D021122:Protein Subunits; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D034501:Telomere-Binding Proteins; C416367:p95 protein, Tetrahymena; D019098:Telomerase; C498417:telomerase p80 protein, Tetrahymena