Targeting assay to study the cis functions of human telomeric proteins: evidence for inhibition of telomerase by TRF1 and for activation of telomere degradation by TRF2.
We investigated the control of telomere length by the human telomeric proteins TRF1 and TRF2. To this end, we established telomerase-positive cell lines in which the targeting of these telomeric proteins to specific telomeres could be induced. We demonstrate that their targeting leads to telomere shortening. This indicates that these proteins act in cis to repress telomere elongation. Inhibition of telomerase activity by a modified oligonucleotide did not further increase the pace of telomere erosion caused by TRF1 targeting, suggesting that telomerase itself is the target of TRF1 regulation. In contrast, TRF2 targeting and telomerase inhibition have additive effects. The possibility that TRF2 can activate a telomeric degradation pathway was directly tested in human primary cells that do not express telomerase. In these cells, overexpression of full-length TRF2 leads to an increased rate of telomere shortening.
Ancelin
Katia
K
Laboratoire de Biologie Moléculaire et Cellulaire, UMR5665 CNRS/ENSL, Ecole Normale Supérieure de Lyon, Lyon, France.
Brunori
Michele
M
Bauwens
Serge
S
Koering
Catherine-Elaine
CE
Brun
Christine
C
Ricoul
Michelle
M
Pommier
Jean-Patrick
JP
Sabatier
Laure
L
Gilson
Eric
E
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D056968:Lac Repressors; D009687:Nuclear Proteins / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D019098:Telomerase / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism*; D035321:Telomeric Repeat Binding Protein 1; D035341:Telomeric Repeat Binding Protein 2; D014162:Transfection
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D056968:Lac Repressors; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D035321:Telomeric Repeat Binding Protein 1; D035341:Telomeric Repeat Binding Protein 2; D019098:Telomerase