Kinetochore components are perinuclear and form condensates in C. elegans germline

Abstract

The kinetochore is a multiprotein complex that assembles on centromeric chromatin and serves as the attachment site for spindle microtubules, thereby ensuring accurate chromosome segregation during cell division. Here we present evidence that kinetochore components, such as HCP-1, form distinct cytoplasmic foci in the C. elegans germline. Prior to cell division, HCP-1 localizes to the nuclear envelope of germ nuclei and forms granules that are distinct from germ granules. Upon mitotic entry, perinuclear HCP-1 is imported into the nucleus to facilitate chromosome segregation. We further show that HCP-1 associates with nuclear pore proteins (NPPs). Loss of NPP-14 disperses perinuclear HCP-1, impairs its nuclear import, and leads to defects in germ cell proliferation and embryonic spindle assembly. Together, these findings provide new insights into the spatial regulation of kinetochore components and their roles in nuclear organization.