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J Biol Chem. 2005 Jul 15;280(28):26586-91. Epub 2005 May 18.

A physical and functional constituent of telomerase anchor site.

Author information

  • 1Department 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

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.

PMID:
15905172
[PubMed - indexed for MEDLINE]
PMCID:
PMC1237055
Free PMC Article
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