Cdc14 targets the Holliday junction resolvase Yen1 to the nucleus in early anaphase

Abstract

The only canonical Holliday junction (HJ) resolvase identified in eukaryotes thus far is Yen1/GEN1. Nevertheless, Yen1/GEN1 appears to have a minor role in HJ resolution, and, instead, other structure-specific endonucleases (SSE) that recognize branched DNA play the leading roles, Mus81-Mms4/EME1 being the most important in budding yeast. Interestingly, cells tightly regulate the activity of each HJ resolvase during the yeast cell cycle. Thus, Mus81-Mms4 is activated in G₂/M, while Yen1 gets activated shortly afterwards. Nevertheless, cytological studies have shown that Yen1 is sequestered out of the nucleus when cyclin-dependent kinase activity is high, i.e., all of the cell cycle but G₁. We here show that the mitotic master phosphatase Cdc14 targets Yen1 to the nucleus in early anaphase through the FEAR network. We will further show that this FEAR-mediated Cdc14-driven event is sufficient to back-up Mus81-Mms4 in removing branched DNA structures, which are especially found in the long chromosome arms upon replication stress. Finally, we found that MEN-driven Cdc14 re-activation in late anaphase is essential to keep Yen1 in the nucleus until the next G₁. Our results highlight the essential role that early-activated Cdc14, i.e., through the FEAR network, has in removing all kind of non-proteinaceous linkages that preclude faithful sister chromatid segregation in anaphase. In addition, our results support the general idea of Yen1 acting as a last resource endonuclease to deal with any remaining HJ that might compromise genetic stability during chromosome segregation.

Keywords: :

• Cdc14
• Yen1
• Mus81-Mms4
• Saccharomyces cerevisiae
• Holliday junction
• anaphase
• MMS

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

We thank Stephen C West for sharing some unpublished data with us and Raimundo Freire for providing the anti-GFP antibody. We also thank other members of our labs for help and discussion. Authors contributed as follows: J.G.L. has performed most of the experimental work. J.G.L., A.C.B., L.A., and F.M. have planned the experiments. L.A. and F.M. have supervised this work. F.M. has written the paper. L.A. hosted J.G.L. in his lab for learning methods related to this work.

Funding

This work was supported by Instituto de Salud Carlos III (PS09/00106 and PS12/00280), Fundación Canaria de Investigación y Salud (08/42 to J.G.L.) and Spanish Ministry of Education (FPU fellowship AP2009-2511 to J.G.L.). All these programs were co-financed with the European Commission's ERDF structural funds