TopBP1 localises to centrosomes in mitosis and to chromosome cores in meiosis
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Topoisomerase IIβ binding protein 1 (TopBP1), previously shown to localise to sites of DNA damage and to stalled replication forks, has been implicated in DNA replication and in DNA damage response. In this work we showed that TopBP1 was localised in structures other than stalled replication forks. In late mitosis TopBP1 localises to centrosomes in a manner similar to other DNA damage response proteins such as BRCA1 and p53. Spindle checkpoint activation does not affect this centrosomal localisation. Moreover, in the testis, we detected high levels of TopBP1 associated with meiotic prophase chromosome cores and the X–Y pair. Together, these data suggest a direct role of TopBP1 during both mitosis and meiotic prophase I.
KeywordsSynaptonemal Complex Nocodazole Meiotic Recombination Spindle Pole Meiotic Prophase
This work was funded by grants from the Academy of Finland and the Cancer Society of Finland. R.F. is supported by FIS (Fondo de Investigaciones Sanitarias) (01/1624) and FUNCIS (Fundación Canaria de Investigación Sanitaria) (PI 45/00) grants. D.P. is supported by a predoctoral fellowship from the Spanish Ministry of Education and Culture. P.B.M is supported by NSERC of Canada. We thank M. Kallio for helpful advice, and H. Pospiech and D. Kaska for editing the manuscript.