Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany.
Nucleic Acids Res. 2018 Nov 30;46(21):11274-11286. doi: 10.1093/nar/gky988.
The evolutionarily conserved nucleoplasmin family of histone chaperones has two paralogues in Drosophila, named Nucleoplasmin-Like Protein (NLP) and Nucleophosmin (NPH). NLP localizes to the centromere, yet molecular underpinnings of this localization are unknown. Moreover, similar to homologues in other organisms, NLP forms a pentamer in vitro, but the biological significance of its oligomerization has not been explored. Here, we characterize the oligomers formed by NLP and NPH in vivo and find that oligomerization of NLP is required for its localization at the centromere. We can further show that oligomerization-deficient NLP is unable to bind the centromeric protein Hybrid Male Rescue (HMR), which in turn is required for targeting the NLP oligomer to the centromere. Finally, using super-resolution microscopy we find that NLP and HMR largely co-localize in domains that are immediately adjacent to, yet distinct from centromere domains defined by the centromeric histone dCENP-A.
在进化上保守的核质素组蛋白伴侣家族在果蝇中有两个同源物，分别命名为核质素样蛋白（NLP）和核磷蛋白（NPH）。NLP 定位于着丝粒，但这种定位的分子基础尚不清楚。此外，与其他生物的同源物类似，NLP 在体外形成五聚体，但它的寡聚化的生物学意义尚未被探索。在这里，我们在体内对 NLP 和 NPH 形成的寡聚体进行了表征，并发现 NLP 的寡聚化对于其在着丝粒的定位是必需的。我们可以进一步表明，寡聚化缺陷的 NLP 无法结合着丝粒蛋白杂种雄性拯救（HMR），而 HMR 反过来又是将 NLP 寡聚体靶向着丝粒所必需的。最后，使用超分辨率显微镜，我们发现 NLP 和 HMR 在很大程度上共定位在与由着丝粒组蛋白 dCENP-A 定义的着丝粒区域相邻但又不同的区域。
