Stimulation of human endonuclease III by Y box-binding protein 1 (DNA-binding protein B). Interaction between a base excision repair enzyme and a transcription factor.
Human endonuclease III (hNth1) is a DNA glycosylase/apurinic/apyrimidinic (AP) lyase that initiates base excision repair of pyrimidines modified by reactive oxygen species, ionizing, and ultraviolet radiation. Using duplex 2'-deoxyribose oligonucleotides containing an abasic (AP) site, a thymine glycol, or a 5-hydroxyuracil residue as substrates, we found the AP lyase activity of hNth1 was 7 times slower than its DNA glycosylase activity, similar to results reported for murine and human 8-oxoguanine-DNA glycosylase, which are also members of the endonuclease III family. This difference in rates contrasts with the equality of rates found in Escherichia coli and Saccharomyces cerevisiae endonuclease III homologs. A yeast two-hybrid screen for potential modulators of hNth1 activity revealed interaction with the damage-inducible transcription factor Y box-binding protein 1 (YB-1), also identified as DNA-binding protein B (DbpB). The in vitro addition of His(6)YB-1 to hNth1 increased the rate of DNA glycosylase and AP lyase activity. Analysis revealed that YB-1 affects the steady state equilibrium between the covalent hNth1-AP site Schiff base ES intermediate and the noncovalent ES intermediate containing the AP aldehydic sugar and the epsilon-amino group of the hNth1 active site lysine. This equilibrium may be a checkpoint in modulating hNth1 activity.
Marenstein
D R
DR
Department of Pathology and Kaplan Comprehensive Cancer Center, New York University School of Medicine, New York, New York 10016, USA.
Ocampo
M T
MT
Chan
M K
MK
Altamirano
A
A
Basu
A K
AK
Boorstein
R J
RJ
Cunningham
R P
RP
Teebor
G W
GW
D020137:Base Pair Mismatch; D022762:CCAAT-Enhancer-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004706:Endodeoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008962:Models, Theoretical; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013379:Substrate Specificity; D014157:Transcription Factors / Q000378:metabolism*; D014466:Ultraviolet Rays; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D004706:Endodeoxyribonucleases; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli; C468347:NTHL1 protein, human