title: A physical and functional constituent of telomerase anchor site.
abstract: Telomerase is a ribonucleoprotein reverse transcriptase responsible for the maintenance of one strand of the telomere terminal repeats. It consists minimally of a catalytic protein component (TERT) and an RNA subunit that provides the template. Compared with prototypical reverse transcriptases, telomerase is unique in possessing a DNA binding domain (anchor site) that is distinct from the catalytic site. Yeast TERT mutants bearing deletion or point mutations in an N-terminal domain (known as N-GQ) were found to be selectively impaired in extending primers that form short hybrids with telomerase RNA. The mutants also suffered a significant loss of repeat addition processivity but displayed an enhancement in nucleotide addition processivity. Furthermore, the mutants manifested altered primer utilization properties for oligonucleotides containing non-telomeric residues in the 5'-region. Cross-linking studies indicate that the N-GQ domain physically contacts the 5'-region of the DNA substrate in the context of a telomerase-telomere complex. Together, these results implicate the N-GQ domain of TERT as a physical and functional constituent of the telomerase anchor site. Coupled with previous genetic analysis, our data confirm that anchor site interaction is indeed important for telomerase function in vivo.
authors.affiliation: Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, Weill Medical College of Cornell University, New York, New York 10021, USA. nflue@med.cornell.edu
authors.forename: Neal F
authors.initials: NF
authors.lastname: Lue
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D020134:Catalytic Domain; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D017931:DNA Primers / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D016812:Euplotes / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry; D017353:Gene Deletion; D066298:In Vitro Techniques; D015233:Models, Statistical; D008969:Molecular Sequence Data; D009154:Mutation; D009841:Oligonucleotides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D017354:Point Mutation; D017434:Protein Structure, Tertiary; D012313:RNA / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D019098:Telomerase / Q000737:chemistry* / Q000378:metabolism; D016615:Telomere / Q000648:ultrastructure; D013768:Tetrahymena / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D017931:DNA Primers; D005656:Fungal Proteins; D009841:Oligonucleotides; D012313:RNA; D004247:DNA; D019098:Telomerase