MEL-28 Is Downstream of the Ran Cycle and Is Required for Nuclear-Envelope Function and Chromatin Maintenance

Fernandez, Anita; Piano, Fabio

doi:10.1016/j.cub.2006.07.071

Cited by 75 publications

(105 citation statements)

References 24 publications

(51 reference statements)

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“…C. elegans, however, does not have an LBR homolog. Several NPC subunits, such as the NPP-5/NUP107 subcomplex and MEL-28/ ELYS, are highly abundant on the C. elegans holocentric chromosome during mitosis (Franz et al 2005;Fernandez and Piano 2006;Galy et al 2006;Rodenas et al 2012). C. elegans studies demonstrated that the chromatin-binding activity of MEL-28/ELYS is conferred by a domain at the C-terminal of the protein (Gomez-Saldivar et al 2016), but it does not depend on the protein's two AT-hook domains, contrary to previous conclusions (Rasala et al 2008).…”

Section: Ne Reassemblymentioning

confidence: 76%

“…Once bound to chromatin, MEL-28/ELYS recruits the NPP-5/NUP107 subcomplex, ultimately leading to the formation of NPCs embedded in the newly formed NE (Franz et al 2007). In the absence of MEL-28/ELYS, the integrity of the newly formed NEs is compromised and they are depleted of both NPCs and nuclear lamina proteins (Fernandez and Piano 2006;Galy et al 2006). The formation of pore-less NEs was also observed after depletion of the NUP107 subcomplex (Harel et al 2003;Walther et al 2003a).…”

Section: Ne Reassemblymentioning

confidence: 99%

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Cell Biology of theCaenorhabditis elegansNucleus

Cohen-Fix

Askjaer

2017

Genetics

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Studies on the Caenorhabditis elegans nucleus have provided fascinating insight to the organization and activities of eukaryotic cells. Being the organelle that holds the genetic blueprint of the cell, the nucleus is critical for basically every aspect of cell biology. The stereotypical development of C. elegans from a one cell-stage embryo to a fertile hermaphrodite with 959 somatic nuclei has allowed the identification of mutants with specific alterations in gene expression programs, nuclear morphology, or nuclear positioning. Moreover, the early C. elegans embryo is an excellent model to dissect the mitotic processes of nuclear disassembly and reformation with high spatiotemporal resolution. We review here several features of the C. elegans nucleus, including its composition, structure, and dynamics. We also discuss the spatial organization of chromatin and regulation of gene expression and how this depends on tight control of nucleocytoplasmic transport. Finally, the extensive connections of the nucleus with the cytoskeleton and their implications during development are described. Most processes of the C. elegans nucleus are evolutionarily conserved, highlighting the relevance of this powerful and versatile model organism to human biology.KEYWORDS Caenorhabditis elegans; chromatin; gene expression; lamin; LEM-domain proteins; LINC; P granule; nuclear pore complex; nuclear envelope; nucleocytoplasmic transport; nucleolus; WormBook TABLE OF CONTENTSAbstract 25 C. elegans as a model system to study cell biology of the nucleus 26 Structural components of the nucleus 27

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Section: Ne Reassemblymentioning

confidence: 76%

Section: Ne Reassemblymentioning

confidence: 99%

Cell Biology of theCaenorhabditis elegansNucleus

Cohen-Fix

Askjaer

2017

Genetics

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“…Chromatin recruits the NE precursor membrane vesicles and nucleoporins to its surface to assemble an NE and the NPCs [5]. In this process, it is thought that the nucleoporin protein ELYS may play an important role in the recruitment of the other nucleoporins Nup107-160 complex onto the chromatin to initiate NPC assembly [6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Chromatin-bound NLS proteins recruit membrane vesicles and nucleoporins for nuclear envelope assembly via importin-α/β

Liu

et al. 2012

Cell Res

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The mechanism for nuclear envelope (NE) assembly is not fully understood. Importin-β and the small GTPase Ran have been implicated in the spatial regulation of NE assembly process. Here we report that chromatin-bound NLS (nuclear localization sequence) proteins provide docking sites for the NE precursor membrane vesicles and nucleoporins via importin-α and -β during NE assembly in Xenopus egg extracts. We show that along with the fast recruitment of the abundant NLS proteins such as nucleoplasmin and histones to the demembranated sperm chromatin in the extracts, importin-α binds the chromatin NLS proteins rapidly. Meanwhile, importin-β binds cytoplasmic NE precursor membrane vesicles and nucleoporins. Through interacting with importin-α on the chromatin NLS proteins, importin-β targets the membrane vesicles and nucleoporins to the chromatin surface. Once encountering Ran-GTP on the chromatin generated by RCC1, importin-β preferentially binds Ran-GTP and releases the membrane vesicles and nucleoporins for NE assembly. NE assembly is disrupted by blocking the interaction between importin-α and NLS proteins with excess soluble NLS proteins or by depletion of importin-β from the extract. Our findings reveal a novel molecular mechanism for NE assembly in Xenopus egg extracts.

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“…In addition, there is growing evidence that NPCs functionally participate in mitosis. Indeed, several kinetochore constituents, including the checkpoint proteins Mad1 and Mad2, are localized to NPCs in interphase; conversely, a growing number of nucleoporins have been found on the mitotic spindle or at kinetochores during mitosis (for reviews, see Stukenberg and Macara, 2003;Hetzer et al, 2005; see also Babu et al, 2003, Liu et al, 2003Arnaoutov et al, 2005;Galy et al, 2006;Fernandez and Piano, 2006;Rasala et al, 2006). Among them, the vertebrate Nup107-160 subcomplex, which is composed in vertebrates of nine subunits (Belgareh et al, 2001;Vasu et al, 2001;Loiodice et al, 2004), contributes to various aspects of cell cycle progression.…”

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confidence: 99%

In Vivo Dynamics ofDrosophilaNuclear Envelope Components

Katsani

Karess

Dostatni

et al. 2008

MBoC

118

128

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Nuclear pore complexes (NPCs) are multisubunit protein entities embedded into the nuclear envelope (NE). Here, we examine the in vivo dynamics of the essential Drosophila nucleoporin Nup107 and several other NE-associated proteins during NE and NPCs disassembly and reassembly that take place within each mitosis. During both the rapid mitosis of syncytial embryos and the more conventional mitosis of larval neuroblasts, Nup107 is gradually released from the NE, but it remains partially confined to the nuclear (spindle) region up to late prometaphase, in contrast to nucleoporins detected by wheat germ agglutinin and lamins. We provide evidence that in all Drosophila cells, a structure derived from the NE persists throughout metaphase and early anaphase. Finally, we examined the dynamics of the spindle checkpoint proteins Mad2 and Mad1. During mitotic exit, Mad2 and Mad1 are actively imported back from the cytoplasm into the nucleus after the NE and NPCs have reformed, but they reassociate with the NE only later in G1, concomitantly with the recruitment of the basket nucleoporin Mtor (the Drosophila orthologue of vertebrate Tpr). Surprisingly, Drosophila Nup107 shows no evidence of localization to kinetochores, despite the demonstrated importance of this association in mammalian cells. INTRODUCTIONIn eukaryotes, the nuclear envelope (NE) defines the limits between the nucleus and the cytoplasm. The outer NE membrane is considered to be structurally and functionally part of the endoplasmic reticulum network, whereas the inner membrane, with its distinct protein composition, provides anchoring points for the chromatin and nuclear lamina. Nuclear pore complexes (NPCs) are embedded at the points of fusion between the inner and outer NE membrane and represent the sole channels of transport across the NE. NPCs are composed of multiple copies of ϳ30 different proteins termed nucleoporins (Nups), most of which are organized into subcomplexes that associate with each other to build up the mature NPCs (for reviews, see Hetzer et al., 2005;Schwartz, 2005;Lim and Fahrenkrog, 2006;Tran and Wente, 2006). During cell division, the NE and NPCs are subjected to major rearrangements. However, the extent to which the NE and NPCs disassemble at mitotic entry varies among organisms (for reviews, see Margalit et al., 2005;Prunuske and Ullman, 2006). Unlike in most yeast and fungi, characterized by a "closed mitosis," NE disassembly is required in animal cells to allow spindle microtubule access to chromosomes. In vertebrates, cell division leads to complete NE breakdown at the prophase-prometaphase transition. During this "open mitosis," integral membrane proteins of the NE and the soluble subcomplexes of the NPCs redistribute throughout the endoplasmic reticulum and the mitotic cytoplasm (for reviews, see Hetzer et al., 2005;Margalit et al., 2005;Prunuske and Ullman, 2006). In Drosophila and Caenorhabditis elegans embryos, however, the NE only partially disassembles near spindle poles in early mitosis. NPCs disassemble during prometapha...

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MEL-28 Is Downstream of the Ran Cycle and Is Required for Nuclear-Envelope Function and Chromatin Maintenance

Cited by 75 publications

References 24 publications

Cell Biology of theCaenorhabditis elegansNucleus

Cell Biology of theCaenorhabditis elegansNucleus

Chromatin-bound NLS proteins recruit membrane vesicles and nucleoporins for nuclear envelope assembly via importin-α/β

In Vivo Dynamics ofDrosophilaNuclear Envelope Components

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