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Y-Box-Binding Protein 1 Stimulates Abasic Site Cleavage

E. E. Alemasova1, K. N. Naumenko1,2, N. A. Moor1, and O. I. Lavrik1,2*

1Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; E-mail: lavrik@niboch.nsc.ru

2Novosibirsk State University, 630090 Novosibirsk, Russia

* To whom correspondence should be addressed.

Received July 12, 2017; Revision received September 6, 2017
Apurinic/apyrimidinic (AP) sites are among the most frequent DNA lesions. The first step in the AP site repair involves the magnesium-dependent enzyme AP endonuclease 1 (APE1) that catalyzes hydrolytic cleavage of the DNA phosphodiester bond at the 5′ side of the AP site, thereby generating a single-strand DNA break flanked by the 3′-OH and 5′-deoxyribose phosphate (dRP) groups. Increased APE1 activity in cancer cells might correlate with tumor chemoresistance to DNA-damaging treatment. It has been previously shown that the multifunctional oncoprotein Y-box-binding protein 1 (YB-1) interacts with APE1 and inhibits APE1-catalyzed hydrolysis of AP sites in single-stranded DNAs. In this work, we demonstrated that YB-1 stabilizes the APE1 complex with double-stranded DNAs containing the AP sites and stimulates cleavage of these AP sites at low magnesium concentrations.
KEY WORDS: Y-box-binding protein 1, AP endonuclease 1, base excision repair, apurinic/apyrimidinic site

DOI: 10.1134/S0006297917120112