The human DINB1 gene encodes the DNA polymerase Poltheta.
The human DINB1 gene shares a high degree of homology with the Escherichia coli dinB gene. Here, we purify the hDINB1-encoded protein and show that it is a DNA polymerase. Because hDinB1 is the eighth eukaryotic DNA polymerase to be described, we have named it DNA polymerase (Pol) theta. hPoltheta is unable to bypass a cis-syn thymine-thymine dimer, nor does it bypass a (6-4) photoproduct or an abasic site. We also examine the fidelity of hPoltheta on nondamaged DNA templates by steady-state kinetic analyses and find that hPoltheta misincorporates deoxynucleotides with a frequency of about 10(-3) to 10(-4). We discuss the relationship between the fidelity of hPoltheta and its inability to bypass DNA damage.
Johnson
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Sealy Center for Molecular Science, University of Texas Medical Branch, 6.014 Medical Research Building, 11th & Mechanic Streets, Galveston, TX 77555-1061, USA.
Prakash
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Prakash
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D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D000097462:DNA Polymerase theta; D000099270:Y-Family DNA Polymerases
D017931:DNA Primers; D004259:DNA-Directed DNA Polymerase; D011506:Proteins; D000097462:DNA Polymerase theta; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases