Transmission electron microscope studies of the nuclear envelope in Caenorhabditis elegans embryos

Cohen, Merav; Tzur, Yonatan B; Neufeld, Esther; Feinstein, Naomi; Delannoy, Michaël; Wilson, Katherine L.; Gruenbaum, Yosef

doi:10.1016/s1047-8477(02)00516-6

Cited by 57 publications

(31 citation statements)

References 31 publications

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“…The integrity of the nuclear envelope was also not affected when other inner nuclear membrane proteins, including emerin, LAP2 (Harborth et al, 2001) and otefin (N. Wagner and G. Krohne, unpublished) (Ashery-Padan et al, 1997), were depleted by RNAi. By contrast, a comparable reduction of lamin Dm0 (this paper) (Lenz-Böhme et al, 1997), the lamin of Caenorhabditis elegans (Liu et al, 2000;Cohen et al, 2002) or lamin B1 or lamin B2 of mammals (Harborth et al, 2001) caused fragility of the nuclear envelope, cell death and developmental arrest (for review, see Gruenbaum et al, 2003).…”

Section: Putative Functions Of the Dlbrmentioning

confidence: 85%

The lamin B receptor of Drosophila melanogaster

Wagner

Weber

Seitz

et al. 2004

Journal of Cell Science

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The lamin B receptor (LBR) is an integral membrane protein of the inner nuclear membrane that has so far been characterized only in vertebrates. Here, we describe the Drosophila melanogaster protein encoded by the annotated gene CG17952 that is the putative ortholog to the vertebrate LBR. The Drosophila lamin B receptor (dLBR) has the following properties in common with the vertebrate LBR. First, structure predictions indicate that the 741 amino acid dLBR protein possesses a highly charged N-terminal domain of 307 amino acids followed by eight transmembrane segments in the C-terminal domain of the molecule. Second, immunolocalization and cell fractionation reveal that the dLBR is an integral membrane protein of the inner nuclear membrane. Third, dLBR can be shown by co-immunoprecipitations and in vitro binding assays to bind to the Drosophila B-type lamin Dm0. Fourth, the N-terminal domain of dLBR is sufficient for in vitro binding to sperm chromatin and lamin Dm0. In contrast to the human LBR, dLBR does not possess sterol C14 reductase activity when it is expressed in the Saccharomyces cerevisiae erg24 mutant, which lacks sterol C14 reductase activity. Our data raise the possibility that, during evolution, the enzymatic activity of this insect protein had been lost.To determine whether the dLBR is an essential protein, we depleted it by RNA interference in Drosophila embryos and in cultured S2 and Kc167 cells. There is no obvious effect on the nuclear architecture or viability of treated cells and embryos, whereas the depletion of Drosophila lamin Dm0 in cultured cells and embryos caused morphological alterations of nuclei, nuclear fragility and the arrest of embryonic development. We conclude that dLBR is not a limiting component of the nuclear architecture in Drosophila cells during the first 2 days of development.

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Section: Putative Functions Of the Dlbrmentioning

confidence: 85%

The lamin B receptor of Drosophila melanogaster

Wagner

Weber

Seitz

et al. 2004

Journal of Cell Science

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“…SD, standard deviation. al., 2001;Lenz-Bohme et al, 1997) and C. elegans cells lacking Ce-lamin (Cohen et al, 2002). The lamin-chromatin interactions are intriguing because of the many ways by which lamins can bind chromatin, either directly or indirectly (Mattout-Drubezki and Gruenbaum, 2003;Pickersgill et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Specific and conserved sequences inD. melanogasterandC. eleganslamins and histone H2A mediate the attachment of lamins to chromosomes

Mattout

Goldberg

Tzur

et al. 2007

Journal of Cell Science

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The intimate association between nuclear lamins and chromatin is thought to regulate higher order chromatin organization. Previous studies have mapped a region between the rod domain and the Ig fold in the tail domain of Drosophila melanogaster lamin Dm0, which binds chromatin in vitro via the histone H2A/H2B dimer. This region contains an evolutionarily conserved nuclear localization signal (NLS) KRKR, and a sequence composed of the amino acids TRAT. Here we show that binding of lamin Dm0 to chromatin requires both NLS and TRAT sequences. Substituting either of the threonine residues in the TRAT sequence with negatively charged residues decreases the binding of lamin Dm0 to chromatin, indicating that this binding could be regulated by phosphorylation. Both lamin Dm0 and C. elegans Ce-lamin bind directly to histone H2A in vitro and this binding requires the NLS. The amino and carboxyl tail domains of histone H2A are each essential, but not sufficient, for binding to lamin Dm0; only a polypeptide containing both histone H2A tail domains binds efficiently to lamin Dm0. Taken together, these results suggest that specific residues in lamin Dm0 and histone H2A mediate the attachment of the nuclear lamina to chromosomes in vivo, which could have implications on the understanding of laminopathic diseases.

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“…In most wild type nuclei, the PNS is consistently 30-50 nm in width, in agreement with previously published results. 29 Surprisingly, nuclei from the null mutant unc-84(n369) strain are not significantly different than the N2 wild type laboratory strain. The PNS of most unc-84 mutant nuclei are evenly spaced throughout, and are not significantly wider than wild type.…”

Section: Unc-84 Maintains the Ne Spacing In Force-bearing Cells But Imentioning

confidence: 94%

SUN proteins and nuclear envelope spacing

Cain

Starr

2014

Nucleus

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T he nuclear envelope consists of 2 membranes separated by 30-50 nm, but how the 2 membranes are evenly spaced has been an open question in the field. Nuclear envelope bridges composed of inner nuclear membrane SUN proteins and outer nuclear membrane KASH proteins have been proposed to set and regulate nuclear envelope spacing. We tested this hypothesis directly by examining nuclear envelope spacing in Caenorhabditis elegans animals lacking UNC-84, the sole somatic SUN protein. SUN/ KASH bridges are not required to maintain even nuclear envelope spacing in most tissues. However, UNC-84 is required for even spacing in body wall muscle nuclei. Shortening UNC-84 by 300 amino acids did not narrow the nuclear envelope space. While SUN proteins may play a role in maintaining nuclear envelope spacing in cells experiencing forces, our data suggest they are dispensable in most cells.

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Transmission electron microscope studies of the nuclear envelope in Caenorhabditis elegans embryos

Cited by 57 publications

References 31 publications

The lamin B receptor of Drosophila melanogaster

The lamin B receptor of Drosophila melanogaster

Specific and conserved sequences inD. melanogasterandC. eleganslamins and histone H2A mediate the attachment of lamins to chromosomes

SUN proteins and nuclear envelope spacing

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