A non transcriptional role for NF-Y in DNA replication

The heterotrimeric transcription factor NF-Y, composed by NF-YA, NF-YB and NF-YC subunits, is a key transcriptional regulator of cell cycle progression. Using data generated by ENCODE, we identified a striking overlap between loci bound by NF-Y-and ORC2, hinting at a possible role of NF-Y in DNA replication. NF-YA knock-down leads to replication defects and the activation an intra-S checkpoint. We investigated the role of NF-Y in DNA replication by using the Xenopus cell-free system. NF-Y subunits were found to be recruited to chromatin during DNA replication. Both immunodepletion of NF-YA or NF-YB and overexpression of a dominant-negative NF-YA mutant lead to a clear decrease in DNA synthesis. In mammalian cells, NF-Y colocalizes and directly interacts with DNA replication proteins. Nascent strand abundance assay in NF-YA inactivated cells corroborates that NF-Y participates to the DNA replication process. Our data highlight that, in addition to its transcriptional activity in controlling cell proliferation, NF-Y plays a key role in the non transcriptional control of DNA replication.