Inhibition of abasic site cleavage in bubble DNA by multifunctional protein YB-1
Résumé
Y-box binding protein 1 (YB-1) is widely known to participate in a multiple DNA and RNA processing events in the
living cell. YB-1 is also regarded as a putative component of DNA repair. This possibility is supported by relocalization
of YB-1 into the nucleus following genotoxic stress. Increased affinity of YB-1 for damaged DNA, especially in its singlestranded
form, and its functional interaction with proteins responsible for the initiation of apurinic/apyrimidinic (AP)
site repair, namely, AP endonuclease 1 and DNA glycosylase NEIL1, suggest that YB-1 could be involved in the repair
of AP sites as a regulatory protein. Here we show that YB-1 has a significant inhibitory effect on the cleavage of AP sites
located in single-stranded DNA and in DNA bubble structures. Such interference may be considered as a possible
mechanismto prevent single-stranded intermediates of DNA replication, transcription and repair frombeing converted
into highly genotoxic DNA strand breaks, thus allowing the cell to coordinate different DNA processing mechanisms.