Inhibition of human telomerase activity by an engineered zinc finger protein that binds G-quadruplexes.
The G-quadruplex nucleic acid structural motif is a target for designing molecules that could potentially modulate telomere length or have anticancer properties. We have recently described an engineered zinc finger protein (Gq1) that binds with specificity to the intramolecular G-quadruplex formed by the human telomeric sequence 5'-(GGTTAG)(5)-3' (Isalan et al. (2001) Biochemistry 40, 830-836). Here, we report that Gq1 is able to arrest the action of a DNA polymerase on a template-containing telomeric sequence. Inhibition occurs in a concentration-dependent manner, probably by forming a stabilized G-quadruplex.protein complex. Furthermore, Gq1 inhibits the apparent activity of the enzyme telomerase in vitro, with an IC(50) value of 74.3 +/- 11.1 nM. Possible molecular mechanisms of inhibition are discussed, together with the potential for using engineered zinc fingers to interfere with the cellular processes associated with telomere function.
Patel
Sachin D
SD
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
Isalan
Mark
M
Gavory
Gérald
G
Ladame
Sylvain
S
Choo
Yen
Y
Balasubramanian
Shankar
S
D004247:DNA / Q000378:metabolism*; D004256:DNA Polymerase I / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D054856:G-Quadruplexes; D006801:Humans; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D015202:Protein Engineering / Q000379:methods; D011500:Protein Synthesis Inhibitors / Q000737:chemistry; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D019098:Telomerase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism*; D016615:Telomere / Q000201:enzymology; D013698:Templates, Genetic; D016335:Zinc Fingers / Q000235:genetics
D004268:DNA-Binding Proteins; D011500:Protein Synthesis Inhibitors; D011993:Recombinant Fusion Proteins; D004247:DNA; D019098:Telomerase; D004256:DNA Polymerase I