TY - JOUR
T1 - A recurrent cancer-associated substitution in DNA polymerase ε produces a hyperactive enzyme
AU - Xing, Xuanxuan
AU - Kane, Daniel P.
AU - Bulock, Chelsea R.
AU - Moore, Elizabeth A.
AU - Sharma, Sushma
AU - Chabes, Andrei
AU - Shcherbakova, Polina V.
N1 - Funding Information:
We thank Erik Johansson for pJL1 and pJL6 plasmids, Peter Burgers for RFC, Krista Brown for technical assistance, and Stephanie Barbari and Youri Pavlov for critically reading the manuscript. This work was supported by the National Institutes of Health grant ES015869 and by Nebraska Department of Health and Human Services grant LB506 to PVS, and by the Swedish Cancer Society and the Swedish Research Council grants to AC. C.R.B. was supported by a University of Nebraska Medical Center Graduate Studies Research Fellowship.
Publisher Copyright:
© 2019, The Author(s).
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Alterations in the exonuclease domain of DNA polymerase ε (Polε) cause ultramutated tumors. Severe mutator effects of the most common variant, Polε-P286R, modeled in yeast suggested that its pathogenicity involves yet unknown mechanisms beyond simple proofreading deficiency. We show that, despite producing a catastrophic amount of replication errors in vivo, the yeast Polε-P286R analog retains partial exonuclease activity and is more accurate than exonuclease-dead Polε. The major consequence of the arginine substitution is a dramatically increased DNA polymerase activity. This is manifested as a superior ability to copy synthetic and natural templates, extend mismatched primer termini, and bypass secondary DNA structures. We discuss a model wherein the cancer-associated substitution limits access of the 3’-terminus to the exonuclease site and promotes binding at the polymerase site, thus stimulating polymerization. We propose that the ultramutator effect results from increased polymerase activity amplifying the contribution of Polε errors to the genomic mutation rate.
AB - Alterations in the exonuclease domain of DNA polymerase ε (Polε) cause ultramutated tumors. Severe mutator effects of the most common variant, Polε-P286R, modeled in yeast suggested that its pathogenicity involves yet unknown mechanisms beyond simple proofreading deficiency. We show that, despite producing a catastrophic amount of replication errors in vivo, the yeast Polε-P286R analog retains partial exonuclease activity and is more accurate than exonuclease-dead Polε. The major consequence of the arginine substitution is a dramatically increased DNA polymerase activity. This is manifested as a superior ability to copy synthetic and natural templates, extend mismatched primer termini, and bypass secondary DNA structures. We discuss a model wherein the cancer-associated substitution limits access of the 3’-terminus to the exonuclease site and promotes binding at the polymerase site, thus stimulating polymerization. We propose that the ultramutator effect results from increased polymerase activity amplifying the contribution of Polε errors to the genomic mutation rate.
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U2 - 10.1038/s41467-018-08145-2
DO - 10.1038/s41467-018-08145-2
M3 - Article
C2 - 30670691
AN - SCOPUS:85060400333
VL - 10
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 374
ER -