A role for Nup153 in nuclear assembly reveals differential requirements for targeting of nuclear envelope constituents

Abstract

Assembly of the nucleus following mitosis requires rapid and coordinate recruitment of diverse constituents to the inner nuclear membrane. We have identified an unexpected role for the nucleoporin Nup153 in promoting the continued addition of a subset of nuclear envelope proteins during initial expansion of nascent nuclei. Specifically, disrupting the function of Nup153 interferes with ongoing addition of B-type lamins, lamin B receptor (LBR), and SUN1 early in telophase, after the nuclear envelope (NE) has initially enclosed chromatin. In contrast, effects on lamin A and SUN2 were minimal, pointing to differential requirements for the ongoing targeting of nuclear envelope proteins. Further, distinct mis-targeting phenotypes arose among the proteins that require Nup153 for NE targeting. Thus, disrupting the function of Nup153 in nuclear formation reveals several previously undescribed features important for establishing nuclear architecture: 1) a role for a nuclear basket constituent in ongoing recruitment of nuclear envelope components, 2) two functionally separable phases of nuclear envelope formation in mammalian cells, and 3) distinct requirements of individual nuclear envelope residents for continued targeting during the expansion phase of NE reformation.

Spermatozoa in mice lacking the nucleoporin NUP210L show defects in head shape and motility but not in nuclear compaction or histone replacement

“…In somatic cells, NUP153 has diverse roles including regulating the export of mRNAs, 16 building chromatin architecture through interactions with CTCF and cohesins, 17 nuclear membrane. 18 In spermatids, the NL is composed of B-type lamins and it is dismantled during spermiogenesis. 19,20 NUP153 might therefore also facilitate B-type lamin extraction from the nucleus and contribute to the breakdown of the spermatid nuclear lamina.…”

“…We identified that the infertile man 13‐4587 9 is heterozygous for a potential pathogenic variant, p.Pro485Leu, in the nucleoporin NUP153, a critical component of the NPC nucleoplasmic basket. In somatic cells, NUP153 has diverse roles including regulating the export of mRNAs, 16 building chromatin architecture through interactions with CTCF and cohesins, 17 and post‐mitotic formation of the nuclear lamina through the targeting of B‐type lamins to the inner nuclear membrane 18 . In spermatids, the NL is composed of B‐type lamins and it is dismantled during spermiogenesis 19,20 .…”

Reconstitution of nuclear envelope subdomain formation on mitotic chromosomes in semi-intact cells

“…However, in this in vitro analysis system, the NE subdomain was not observed. Differential accumulation of INM proteins on chromosomes at the early step of NE assembly seems to be a general phenomenon in human cells (Maeshima et al, 2006) and has been precisely described in HeLa cells (Clever et al, 2012;Haraguchi et al, 2001;LaJoie et al, 2022). Therefore, we attempted to reconstitute an in vitro NE reassembly system in human cells that would recapitulate the phenomena observed in living mitotic cells.…”