TY - JOUR
T1 - Regulation of catalytic activity and processivity of human telomerase
AU - Sun, Daekyu
AU - Lopez-Guajardo, Christine C.
AU - Quada, James
AU - Hurley, Laurence H.
AU - Von Hoff, Daniel D.
PY - 1999/3/30
Y1 - 1999/3/30
N2 - The ends of eukaryotic chromosomes are specialized sequences, called telomeres comprising tandem repeats of simple DNA sequences. Those sequences are essential for preventing aberrant recombination and protecting genomic DNA against exonucleolytic DNA degradation. Telomeres are maintained at a stable length by telomerase, an RNA-dependent DNA polymerase. Recently, human telomerase has been recognized as a unique diagnostic marker for human tumors and is potentially a highly selective target for antitumor drugs. In this study, we have examined the major factors affecting the catalytic activity and processivity of human telomerase. Specifically, both the catalytic activity and processivity of human telomerase were modulated by temperature, substrate (dNTP and primer) concentration, and the concentration of K+. The catalytic activity of telomerase increased as temperature (up to 37°C), concentrations of dGTP, primer, and K+ were increased. However, the processivity of human telomerase decreased as temperature, primer concentration, and K+ were increased. Our results support the current model for human telomerase reaction and strengthen the hypothesis that a G- quadruplex structure of telomere DNA plays an important role in the regulation of the telomerase reaction.
AB - The ends of eukaryotic chromosomes are specialized sequences, called telomeres comprising tandem repeats of simple DNA sequences. Those sequences are essential for preventing aberrant recombination and protecting genomic DNA against exonucleolytic DNA degradation. Telomeres are maintained at a stable length by telomerase, an RNA-dependent DNA polymerase. Recently, human telomerase has been recognized as a unique diagnostic marker for human tumors and is potentially a highly selective target for antitumor drugs. In this study, we have examined the major factors affecting the catalytic activity and processivity of human telomerase. Specifically, both the catalytic activity and processivity of human telomerase were modulated by temperature, substrate (dNTP and primer) concentration, and the concentration of K+. The catalytic activity of telomerase increased as temperature (up to 37°C), concentrations of dGTP, primer, and K+ were increased. However, the processivity of human telomerase decreased as temperature, primer concentration, and K+ were increased. Our results support the current model for human telomerase reaction and strengthen the hypothesis that a G- quadruplex structure of telomere DNA plays an important role in the regulation of the telomerase reaction.
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U2 - 10.1021/bi982249n
DO - 10.1021/bi982249n
M3 - Article
C2 - 10194316
AN - SCOPUS:0033616833
SN - 0006-2960
VL - 38
SP - 4037
EP - 4044
JO - Biochemistry
JF - Biochemistry
IS - 13
ER -