Telomerase core components protect Candida telomeres from aberrant overhang accumulation.
Telomerase is a cellular reverse transcriptase that extends one strand (the G-strand) of the telomere terminal repeats. Aside from this role in telomere length maintenance, telomerase has been proposed to serve a protective function at chromosome ends, although this is not well understood mechanistically. Earlier analysis suggests that, in the pathogenic yeast Candida albicans, the catalytic reverse transcriptase subunit of telomerase (TERT/EST2) can protect telomeres against nucleolytic degradation. In this report we demonstrate that the RNA component (TER1) has a similar function; in addition to complete loss of telomerase activity and progressive telomere attrition, the ter1-DeltaDelta strains manifested a dramatic increase in the amount of G-strand overhangs, consistent with aberrant degradation of the complementary C-strand. We also demonstrate that a catalytically incompetent EST2 protein can suppress such overhang accumulation in the est2-DeltaDelta mutant to the same extent as the wild-type protein. Altogether, our data support the notion that the Candida telomerase core components mediate a protective function through a mechanism that is independent of its catalytic activity.
Hsu
Min
M
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.
McEachern
Michael J
MJ
Dandjinou
Alain T
AT
Tzfati
Yehuda
Y
Orr
Erica
E
Blackburn
Elizabeth H
EH
Lue
Neal F
NF
D002175:Candida / Q000201:enzymology* / Q000235:genetics; D004271:DNA, Fungal / Q000378:metabolism*; D012313:RNA / Q000502:physiology*; D019098:Telomerase / Q000235:genetics / Q000502:physiology*; D016615:Telomere / Q000235:genetics / Q000378:metabolism*
D004271:DNA, Fungal; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase