TY - JOUR
T1 - Developmentally programmed gene elimination in Euplotes crassus facilitates a switch in the telomerase catalytic subunit
AU - Karamysheva, Zemfira
AU - Wang, Libin
AU - Shrode, Timothy
AU - Bednenko, Janna
AU - Hurley, Leigh Anne
AU - Shippen, Dorothy E.
N1 - Funding Information:
We thank Larry Klobutcher, Linda Guarino, Jeff Kapler, and Andrey Karamyshev for insightful comments on the manuscript, and Larry Klobutcher and Mary Ellen Jacobs for providing instructions on monitoring Tec3 excision. This work was supported by National Institutes of Health grant GM49157 to D.E.S.
PY - 2003/5/30
Y1 - 2003/5/30
N2 - The primary function of telomerase is to maintain preexisting telomere tracts. In the ciliate Euplotes crassus, however, telomerase RNP structure and substrate recognition are altered during macronuclear development to facilitate de novo telomere addition. We found that E. crassus harbors three TERT genes encoding the telomerase catalytic subunit that not only vary in their nucleotide and predicted protein sequences, but also in their expression profiles. Expression of EcTERT-1 and -3 correlates with the requirement for telomere maintenance, while that of EcTERT-2 correlates with de novo telomere synthesis. All three genes appear to require ribosomal frameshifting for expression of catalytically active protein. The transcriptionally active form of EcTERT-2 exists only transiently in mated cells and is absent from the vegetative macronucleus. Thus, telomerase expression in Euplotes is controlled by unique regulatory mechanisms that culminate in a developmental switch to a different catalytic subunit with properties suited to de novo telomere addition.
AB - The primary function of telomerase is to maintain preexisting telomere tracts. In the ciliate Euplotes crassus, however, telomerase RNP structure and substrate recognition are altered during macronuclear development to facilitate de novo telomere addition. We found that E. crassus harbors three TERT genes encoding the telomerase catalytic subunit that not only vary in their nucleotide and predicted protein sequences, but also in their expression profiles. Expression of EcTERT-1 and -3 correlates with the requirement for telomere maintenance, while that of EcTERT-2 correlates with de novo telomere synthesis. All three genes appear to require ribosomal frameshifting for expression of catalytically active protein. The transcriptionally active form of EcTERT-2 exists only transiently in mated cells and is absent from the vegetative macronucleus. Thus, telomerase expression in Euplotes is controlled by unique regulatory mechanisms that culminate in a developmental switch to a different catalytic subunit with properties suited to de novo telomere addition.
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U2 - 10.1016/S0092-8674(03)00363-5
DO - 10.1016/S0092-8674(03)00363-5
M3 - Article
C2 - 12787498
AN - SCOPUS:0037806033
SN - 0092-8674
VL - 113
SP - 565
EP - 576
JO - Cell
JF - Cell
IS - 5
ER -