Nuclear pore absence from areas of close association between nucleus and vacuole in synchronous yeast cultures

Severs, N. J.; Jordan, E. G.; Williamson, D. H.

doi:10.1016/s0022-5320(76)80023-8

Cited by 57 publications

(54 citation statements)

References 42 publications

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“…Figure 6 shows the results of an experiment using diploid cells incubated at 23°C. For wild-type cells, NPCs were distributed around the nuclear envelope ( Figure 6A), although occasional local concentrations were observed, as has been previously reported (Severs et al, 1976). In contrast, in diploid cells homozygous for the rat3-1 mutation, NPCs were observed primarily in one or two discrete areas of the nuclear envelope.…”

Section: Npc Ags Are Mislocalized In Yeast Strainssupporting

confidence: 79%

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Mutation or deletion of the Saccharomyces cerevisiae RAT3/NUP133 gene causes temperature-dependent nuclear accumulation of poly(A)+ RNA and constitutive clustering of nuclear pore complexes.

Heath

Amberg

et al. 1995

MBoC

119

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To identify genes whose products play potential roles in the nucleocytoplasmic export of messenger RNA, we isolated temperature-sensitive strains of Saccharomyces cerevisiae and examined them by fluorescent in situ hybridization. With the use of a digoxigen-tagged oligo-(dT)50 probe, we identified those that showed nuclear accumulation of poly(A)+ RNA when cells were shifted to the nonpermissive temperature. We describe here the properties of yeast strains bearing the rat3-1 mutation (RAT -ribonucleic acid trafficking) and the cloning of the RAT3 gene. When cultured at the permissive temperature of 23°C, fewer than 10% of cells carrying the rat3-1 allele showed nuclear accumulation of poly(A)+ RNA, whereas approximately 70% showed nuclear accumulation of poly(A)+ RNA after a shift to 37°C for 4 h. In wild-type cells, nuclear pore complexes (NPCs) are distributed relatively evenly around the nuclear envelope. Both indirect immunofluorescence analysis and electron microscopy of rat3-1 cells indicated that NPCs were clustered into one or a few regions of the NE in mutant cells. Similar NPC clustering was seen in mutant cells cultured at temperatures between 15°C and 37°C. The RAT3 gene encodes an 1157-amino acid protein without similarity to other known proteins. It is essential for growth only at 37°C. Cells carrying a disruption of the RAT3 gene were very similar to cells carrying the original rat3-1 mutation; they showed temperature-dependent nuclear accumulation of poly(A)+ RNA and exhibited constitutive clustering of NPCs. Epitope tagging of Rat3p demonstrated that it is located at the nuclear periphery and co-localizes with nuclear pore proteins recognized by the RL1 monoclonal antibody. We refer to this nucleoporin as Rat3p/Nupl33p.

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Section: Npc Ags Are Mislocalized In Yeast Strainssupporting

confidence: 79%

“…NPCs are usually evenly distributed around the nucleus in most somatic cell types [reviewed by (Maul, 1977)], including yeast, although the distribution may not be perfectly random (Severs et al, 1976). Several specialized cell types have highly ordered NPC arrangements.…”

Section: Discussionmentioning

confidence: 99%

Mutation or deletion of the Saccharomyces cerevisiae RAT3/NUP133 gene causes temperature-dependent nuclear accumulation of poly(A)+ RNA and constitutive clustering of nuclear pore complexes.

Heath

Amberg

et al. 1995

MBoC

119

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“…11 Electron micrographs of yeast cells have long exposed areas of close membrane contact between these two organelles. 12 Severs et al 12 first noted that NV junctions appeared to be devoid of nuclear pore complexes, which we later confirmed. 4,11 Others noted that yeast nuclei and vacuoles moved about the cytoplasm as if attached.…”

Section: Pmn Occurs In the Context Of Nucleus-vacuole (Nv) Junctionssupporting

confidence: 69%

Nucleus-Vacuole Junctions and Piecemeal Microautophagy of the Nucleus inS. cerevisiae

Kvam

Goldfarb²

2007

Autophagy

108

117

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Previously published online as an AcKnowlEDGEmEntSWe wish to thank past and present lab members who have contributed their ideas and technical assistance to this project, especially Jonathan Millen who made comments on this manuscript, and to our many helpful and supportive colleagues in the autophagy research community. This study was supported by grants from the National Science Foundation and National Institutes of Health. AbStrActVarious modes of autophagy conspire to degrade virtually every compartment of the eukaryotic cell. In Saccharomyces cerevisiae, a process called "piecemeal microautophagy of the nucleus" (PMN) even pinches off and degrades nonessential portions of the nucleus. PMN is a constitutive process induced to high levels by starvation or rapamycin, an inhibitor of TOR kinase. PMN occurs at nucleus-vacuole (NV) junctions, which are Velcro-like patches formed by interactions between the vacuole membrane protein Vac8p and the outer-nuclear-membrane protein Nvj1p. In response to nutrient depletion, Nvj1p increasingly binds and sequesters two proteins with roles in lipid metabolism, Osh1p and Tsc13p. Tsc13p is required for the normal biogenesis of PMN vesicles. The sequestration of Osh1p by Nvj1p likely serves to negatively regulate the trafficking of tryptophan permease(s) to the plasma membrane. Thus, NV junctions and PMN orchestrate novel and sophisticated responses to nutrient limitation.

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“…These changes are distinct from other alterations of NPCs and the nuclear envelope which have been previously reported. For example, the distribution and size of nuclear pores change during the cell cycle (75,89). Moreover, mutation of individual nuclear pore proteins can cause clustering of NPCs (Nsp1p [58] and nup133/rat3 and nup159/rat7 [21,24,51]), intranuclear annulate lamellae and "herniated NPCs" (nup116 [86]), grape-like clusters of NPC herniations (nup145 [87]), and impressive elaborations of the undilated nuclear membrane into the cytoplasm (nup1 [9]).…”

Section: Discussionmentioning

confidence: 99%

A Yeast Acetyl Coenzyme A Carboxylase Mutant Links Very-Long-Chain Fatty Acid Synthesis to the Structure and Function of the Nuclear Membrane-Pore Complex

Schneiter

Hitomi

Ivessa

et al. 1996

Molecular and Cellular Biology

182

185

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The conditional mRNA transport mutant of Saccharomyces cerevisiae, acc1-7-1 (mtr7-1), displays a unique alteration of the nuclear envelope. Unlike nucleoporin mutants and other RNA transport mutants, the intermembrane space expands, protuberances extend from the inner membrane into the intermembrane space, and vesicles accumulate in the intermembrane space. MTR7 is the same gene as ACC1, encoding acetyl coenzyme A (CoA) carboxylase (Acc1p), the rate-limiting enzyme of de novo fatty acid synthesis. Genetic and biochemical analyses of fatty acid synthesis mutants and acc1-7-1 indicate that the continued synthesis of malonyl-CoA, the enzymatic product of acetyl-CoA carboxylase, is required for an essential pathway which is independent from de novo synthesis of fatty acids. We provide evidence that synthesis of very-long-chain fatty acids (C 26 atoms) is inhibited in acc1-7-1, suggesting that very-long-chain fatty acid synthesis is required to maintain a functional nuclear envelope.The regulation of synthesis and transport of phospholipids has been characterized at length, but the signals which determine the phospholipid and fatty acid composition of particular membranes and membrane-specific lipid requirements are not well understood (7,62,81,83). The present investigation, which is the outgrowth of analysis of a yeast (Saccharomyces cerevisiae) mutant which accumulates poly(A) ϩ RNA in the nucleus at the restrictive temperature (41), documents a critical relationship between fatty acid chain length and the integrity of the nuclear membrane and nuclear pore complex (NPC).The biosynthesis of very-long-chain fatty acids requires four enzyme systems: acetyl coenzyme A (CoA) carboxylase, fatty acid synthase, fatty acid desaturase, and the fatty acyl chain elongation system (Fig. 1). The rate-limiting step of the de novo synthesis of fatty acids is under control of the first of these, acetyl-CoA carboxylase (Acc1p; EC 6.4.1.2). This biotinylated enzyme catalyzes the ATP-dependent carboxylation of acetyl-CoA to yield malonyl-CoA, which serves as the twocarbon-unit donor for the subsequent synthesis of long-chain fatty acids by the fatty acid synthase complex. The chain length of newly synthesized fatty acids appears to depend on the concentration of malonyl-CoA rather than on the activity of the fatty acid synthase complex (35, 43a, 82). Acc1p thus regulates both the overall rate of de novo synthesis and chainlength distribution of long-chain fatty acids. It is perhaps for this reason that its activity is subject to complex regulation (48). Yeast Acc1p/Fas3p has a subunit molecular mass of 250 kDa, is active as a tetramer, and is subject to short-term regulation by phosphorylation (2, 60, 90). Its transcription is positively regulated by Ino2p and Ino4p and negatively regulated by Opi1p; i.e., it is under the general control of phospholipid synthesis (14, 31).Many yeast long-chain fatty acid auxotrophs have been isolated (72). Sixty-one are alleles of acc1 (55, 67), while others bear mutations in fatty acid synthase (19,...

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Nuclear pore absence from areas of close association between nucleus and vacuole in synchronous yeast cultures

Cited by 57 publications

References 42 publications

Mutation or deletion of the Saccharomyces cerevisiae RAT3/NUP133 gene causes temperature-dependent nuclear accumulation of poly(A)+ RNA and constitutive clustering of nuclear pore complexes.

Mutation or deletion of the Saccharomyces cerevisiae RAT3/NUP133 gene causes temperature-dependent nuclear accumulation of poly(A)+ RNA and constitutive clustering of nuclear pore complexes.

Nucleus-Vacuole Junctions and Piecemeal Microautophagy of the Nucleus inS. cerevisiae

A Yeast Acetyl Coenzyme A Carboxylase Mutant Links Very-Long-Chain Fatty Acid Synthesis to the Structure and Function of the Nuclear Membrane-Pore Complex

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