Telomerase can act as a template- and RNA-independent terminal transferase.
Telomerase is a special reverse transcriptase that extends one strand of the telomere repeat by using a template embedded in an RNA subunit. Like other polymerases, telomerase is believed to use a pair of divalent metal ions (coordinated by a triad of aspartic acid residues) for catalyzing nucleotide addition. Here we show that, in the presence of manganese, both yeast and human telomerase can switch to a template- and RNA-independent mode of DNA synthesis, acting in effect as a terminal transferase. Even as a terminal transferase, yeast telomerase retains a species-dependent preference for GT-rich, telomere-like DNA on the 5' end of the substrate. The terminal transferase activity of telomerase may account for some of the hitherto unexplained effects of telomerase overexpression on cell physiology.
Lue
Neal F
NF
Department of Microbiology and Immunology, W. R. Hearst Microbiology Research Center, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA. nflue@med.cornell.edu
Bosoy
Dimitry
D
Moriarty
Tara J
TJ
Autexier
Chantal
C
Altman
Brian
B
Leng
Siyang
S
D001483:Base Sequence; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D004261:DNA Replication / Q000502:physiology*; D004586:Electrophoresis; D006801:Humans; D008345:Manganese / Q000378:metabolism*; D012156:Reticulocytes / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D019098:Telomerase / Q000378:metabolism*; D016615:Telomere / Q000235:genetics; D014166:Transferases / Q000378:metabolism*
D017931:DNA Primers; D008345:Manganese; D004247:DNA; D014166:Transferases; D019098:Telomerase