title: Regulation of telomere length and function by a Myb-domain protein in fission yeast.
abstract: Telomeres, the specialized nucleoprotein structures that comprise the ends of eukaryotic chromosomes, are essential for complete replication, and regulation of their length has been a focus of research on tumorigenesis. In the budding yeast Saccharomyces cerevisiae, the protein Rap1p binds to telomeric DNA and functions in the regulation of telomere length. A human telomere protein, hTRF (human TTAGGG repeat factor) binds the telomere sequence in vitro and localizes to telomeres cytologically, but its functions are not yet known. Here we use a genetic screen to identify a telomere protein in fission yeast, Taz1p (telomere-associated in Schizosaccharomyces pombe), that shares homology to the Myb proto-oncogene DNA-binding domain with hTRF. Disruption or deletion of the taz1+ gene causes a massive increase in telomere length. Taz1p is required for the repression of telomere-adjacent gene expression and for normal meiosis or sporulation. It may be a negative regulator of the telomere-replicating enzyme, telomerase, or may protect against activation of telomerase-independent pathways of telomere elongation.
authors.affiliation: Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Cooper
authors.forename: E R
authors.initials: ER
authors.lastname: Nimmo
authors.forename: R C
authors.initials: RC
authors.lastname: Allshire
authors.forename: T R
authors.initials: TR
authors.lastname: Cech
mesh_terms: D000595:Amino Acid Sequence; D015825:Chromosomes, Fungal / Q000378:metabolism; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000737:chemistry*; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal; D016615:Telomere / Q000378:metabolism*; D034501:Telomere-Binding Proteins; D015534:Trans-Activators / Q000737:chemistry*
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; D034501:Telomere-Binding Proteins; D015534:Trans-Activators; C104344:taz1 protein, S pombe