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Isaac R, Vinik Y, Mikl M, Nadav-Eliyahu S, Shatz-Azoulay H, Yaakobi A, DeForest N, Majithia AR, Webster NJ, Shav-Tal Y, Elhanany E, Zick Y. A seven-transmembrane protein-TM7SF3, resides in nuclear speckles and regulates alternative splicing. iScience 2022; 25:105270. [PMID: 36304109 PMCID: PMC9593240 DOI: 10.1016/j.isci.2022.105270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 06/08/2022] [Accepted: 09/26/2022] [Indexed: 11/17/2022] Open
Abstract
The seven-transmembrane superfamily member 3 protein (TM7SF3) is a p53-regulated homeostatic factor that attenuates cellular stress and the unfolded protein response. Here we show that TM7SF3 localizes to nuclear speckles; eukaryotic nuclear bodies enriched in splicing factors. This unexpected location for a trans -membranal protein enables formation of stable complexes between TM7SF3 and pre-mRNA splicing factors including DHX15, LARP7, HNRNPU, RBM14, and HNRNPK. Indeed, TM7SF3 regulates alternative splicing of >330 genes, mainly at the 3'end of introns by directly modulating the activity of splicing factors such as HNRNPK. These effects are observed both in cell lines and primary human pancreatic islets. Accordingly, silencing of TM7SF3 results in differential expression of 1465 genes (about 7% of the human genome); with 844 and 621 genes being up- or down-regulated, respectively. Our findings implicate TM7SF3, as a resident protein of nuclear speckles and suggest a role for seven-transmembrane proteins as regulators of alternative splicing.
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Affiliation(s)
- Roi Isaac
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Yaron Vinik
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Martin Mikl
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Biology, University of Haifa, Haifa, Israel
| | - Shani Nadav-Eliyahu
- The Mina & Everard Goodman Faculty of Life Sciences and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Hadas Shatz-Azoulay
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Adi Yaakobi
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Natalie DeForest
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, CA 92093, USA
| | - Amit R. Majithia
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Nicholas J.G. Webster
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA, USA
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Yaron Shav-Tal
- The Mina & Everard Goodman Faculty of Life Sciences and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Eytan Elhanany
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yehiel Zick
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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Stiekema M, Houben F, Verheyen F, Borgers M, Menzel J, Meschkat M, van Zandvoort MAMJ, Ramaekers FCS, Broers JLV. The Role of Lamins in the Nucleoplasmic Reticulum, a Pleiomorphic Organelle That Enhances Nucleo-Cytoplasmic Interplay. Front Cell Dev Biol 2022; 10:914286. [PMID: 35784476 PMCID: PMC9243388 DOI: 10.3389/fcell.2022.914286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/24/2022] [Indexed: 12/15/2022] Open
Abstract
Invaginations of the nuclear membrane occur in different shapes, sizes, and compositions. Part of these pleiomorphic invaginations make up the nucleoplasmic reticulum (NR), while others are merely nuclear folds. We define the NR as tubular invaginations consisting of either both the inner and outer nuclear membrane, or only the inner nuclear membrane. Specifically, invaginations of both the inner and outer nuclear membrane are also called type II NR, while those of only the inner nuclear membrane are defined as type I NR. The formation and structure of the NR is determined by proteins associated to the nuclear membrane, which induce a high membrane curvature leading to tubular invaginations. Here we review and discuss the current knowledge of nuclear invaginations and the NR in particular. An increase in tubular invaginations of the nuclear envelope is associated with several pathologies, such as laminopathies, cancer, (reversible) heart failure, and Alzheimer’s disease. Furthermore, viruses can induce both type I and II NR. In laminopathies, the amount of A-type lamins throughout the nucleus is generally decreased or the organization of lamins or lamin-associated proteins is disturbed. Also, lamin overexpression or modulation of lamin farnesylation status impacts NR formation, confirming the importance of lamin processing in NR formation. Virus infections reorganize the nuclear lamina via (de)phosphorylation of lamins, leading to an uneven thickness of the nuclear lamina and in turn lobulation of the nuclear membrane and the formation of invaginations of the inner nuclear membrane. Since most studies on the NR have been performed with cell cultures, we present additional proof for the existence of these structures in vivo, focusing on a variety of differentiated cardiovascular and hematopoietic cells. Furthermore, we substantiate the knowledge of the lamin composition of the NR by super-resolution images of the lamin A/C and B1 organization. Finally, we further highlight the essential role of lamins in NR formation by demonstrating that (over)expression of lamins can induce aberrant NR structures.
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Affiliation(s)
- Merel Stiekema
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
- GROW-School for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Frederik Houben
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
- Department of Healthcare, PXL University College, Hasselt, Belgium
| | - Fons Verheyen
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Marcel Borgers
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | | | | | - Marc A. M. J. van Zandvoort
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
- GROW-School for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, Netherlands
- CARIM-School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, Netherlands
- Institute for Molecular Cardiovascular Research IMCAR, RWTH Aachen University, Aachen, Germany
| | - Frans C. S. Ramaekers
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
- GROW-School for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Jos L. V. Broers
- Department of Genetics and Cell Biology, Maastricht University Medical Centre, Maastricht, Netherlands
- GROW-School for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, Netherlands
- CARIM-School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, Netherlands
- *Correspondence: Jos L. V. Broers,
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3
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Preston CC, Stoddard AC, Faustino RS. A Transient Mystery: Nucleolar Channel Systems. Results Probl Cell Differ 2022; 70:581-593. [PMID: 36348122 DOI: 10.1007/978-3-031-06573-6_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The nucleus is a complex organelle with functions beyond being a simple repository for genomic material. For example, its actions in biomechanical sensing, protein synthesis, and epigenomic regulation showcase how the nucleus integrates multiple signaling modalities to intricately regulate gene expression. This innate dynamism is underscored by subnuclear components that facilitate these roles, with elements of the nucleoskeleton, phase-separated nuclear bodies, and chromatin safeguarding by nuclear envelope proteins providing examples of this functional diversity. Among these, one of the lesser characterized nuclear organelles is the nucleolar channel system (NCS), first reported several decades ago in human endometrial biopsies. This tubular structure, believed to be derived from the inner nuclear membrane of the nuclear envelope, was first observed in secretory endometrial cells during a specific phase of the menstrual cycle. Reported as a consistent, yet transient, nuclear organelle, current interpretations of existing data suggest that it serves as a marker of a window for optimal implantation. In spite of this available data, the NCS remains incompletely characterized structurally and functionally, due in part to its transient spatial and temporal expression. As a further complication, evidence exists showing NCS expression in fetal tissue, suggesting that it may not act exclusively as a marker of uterine receptivity, but rather as a hormone sensor sensitive to estrogen and progesterone ratios. To gain a better understanding of the NCS, current technologies can be applied to profile rare cell populations or capture transient structural dynamics, for example, at a level of sensitivity and resolution not previously possible. Moving forward, advanced characterization of the NCS will shed light on an uncharacterized aspect of reproductive physiology, with the potential to refine assisted reproductive techniques.
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Affiliation(s)
- Claudia C Preston
- Biology Department, St. Mary's University of Minnesota, Winona, MN, USA
| | | | - Randolph S Faustino
- Genetics and Genomics Group, Sanford Research, Sioux Falls, SD, USA.
- Department of Pediatrics, Sanford School of Medicine of the University of South Dakota, Sioux Falls, SD, USA.
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4
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Zhu WJ. Transmission electron microscopy analysis of the origin and incidence of sperm intranuclear cytoplasmic retention in fertile and teratozoospermia men. Andrology 2018; 6:317-324. [PMID: 29457364 DOI: 10.1111/andr.12469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 12/31/2017] [Accepted: 01/02/2018] [Indexed: 11/27/2022]
Abstract
The human sperm nucleus contains cytoplasm. However, the origin and incidence of human sperm intranuclear cytoplasmic retention (INCR) remain unknown. The objectives of this study were to observe the morphological origin of INCR within the seminiferous epithelium and investigate the incidence of INCR in fertile and teratozoospermia men using transmission electron microscopy (TEM). By TEM, INCR initially appeared in elongating round spermatid nuclei and varied in size, number, shape, content, location and distribution within sperm nuclei. The teratozoospermia group (n = 16) demonstrated a higher incidence of INCR than did the fertile group (n = 16) (17.6 ± 5.2% vs. 9.7 ± 3.4%; p = 0.000). In the fertile group, no correlations were found between the incidence of INCR and abnormal sperm morphology, nuclear vacuole, acrosome integrity, motility or concentration (p > 0.05). However, the incidence of INCR exhibited a positive relationship with sperm abnormal morphology in the teratozoospermia group (r = 0.616, p = 0.011). These results demonstrate that INCR occurs in the early process of spermatogenesis and is an alteration found in the nucleus. Spermatozoa from teratozoospermia men contained more INCRs than those from fertile males. More attention should be paid to the possibility of spermatozoa containing INCR when using spermatozoa with abnormal head morphology for clinical or diagnostic purposes.
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Affiliation(s)
- W-J Zhu
- Department of Developmental and Regenerative Biology, College of Life Science and Technology, Jinan University, Guangzhou, China
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5
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Yuan F, Zhang Y, Ma L, Cheng Q, Li G, Tong T. Enhanced NOLC1 promotes cell senescence and represses hepatocellular carcinoma cell proliferation by disturbing the organization of nucleolus. Aging Cell 2017; 16:726-737. [PMID: 28493459 PMCID: PMC5506443 DOI: 10.1111/acel.12602] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2017] [Indexed: 01/11/2023] Open
Abstract
The nucleolus is a key organelle that is responsible for the synthesis of rRNA and assembly of ribosomal subunits, which is also the center of metabolic control because of the critical role of ribosomes in protein synthesis. Perturbations of rRNA biogenesis are closely related to cell senescence and tumor progression; however, the underlying molecular mechanisms are not well understood. Here, we report that cellular senescence‐inhibited gene (CSIG) knockdown up‐regulated NOLC1 by stabilizing the 5′UTR of NOLC1 mRNA, and elevated NOLC1 induced the retention of NOG1 in the nucleolus, which is responsible for rRNA processing. Besides, the expression of NOLC1 was negatively correlated with CSIG in the aged mouse tissue and replicative senescent 2BS cells, and the down‐regulation of NOLC1 could rescue CSIG knockdown‐induced 2BS senescence. Additionally, NOLC1 expression was decreased in human hepatocellular carcinoma (HCC) tissue, and the ectopic expression of NOLC1 repressed the proliferation of HCC cells and tumor growth in a HCC xenograft model.
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Affiliation(s)
- Fuwen Yuan
- Peking University Research Center on Aging; Department of Biochemistry and Molecular Biology; Peking University Health Science Center, Beijing, Key Laboratory of Protein Posttranslational Modifications and Cell Function; Beijing 100191 China
| | - Yu Zhang
- Peking University Research Center on Aging; Department of Biochemistry and Molecular Biology; Peking University Health Science Center, Beijing, Key Laboratory of Protein Posttranslational Modifications and Cell Function; Beijing 100191 China
| | - Liwei Ma
- Peking University Research Center on Aging; Department of Biochemistry and Molecular Biology; Peking University Health Science Center, Beijing, Key Laboratory of Protein Posttranslational Modifications and Cell Function; Beijing 100191 China
| | - Qian Cheng
- Peking University Research Center on Aging; Department of Biochemistry and Molecular Biology; Peking University Health Science Center, Beijing, Key Laboratory of Protein Posttranslational Modifications and Cell Function; Beijing 100191 China
- Department of Hepatobilliary Surgery; Beijing, Key Surgical Basic Research Laboratory of Liver Cirrhosis and Liver Cancer; Peking University People's Hospital; Beijing 100044 China
| | - Guodong Li
- Peking University Research Center on Aging; Department of Biochemistry and Molecular Biology; Peking University Health Science Center, Beijing, Key Laboratory of Protein Posttranslational Modifications and Cell Function; Beijing 100191 China
| | - Tanjun Tong
- Peking University Research Center on Aging; Department of Biochemistry and Molecular Biology; Peking University Health Science Center, Beijing, Key Laboratory of Protein Posttranslational Modifications and Cell Function; Beijing 100191 China
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6
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Drozdz MM, Vaux DJ. Shared mechanisms in physiological and pathological nucleoplasmic reticulum formation. Nucleus 2017; 8:34-45. [PMID: 27797635 PMCID: PMC5287099 DOI: 10.1080/19491034.2016.1252893] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/13/2016] [Accepted: 10/19/2016] [Indexed: 12/14/2022] Open
Abstract
The mammalian nuclear envelope (NE) can develop complex dynamic membrane-bounded invaginations in response to both physiological and pathological stimuli. Since the formation of these nucleoplasmic reticulum (NR) structures can occur during interphase, without mitotic NE breakdown and reassembly, some other mechanism must drive their development. Here we consider models for deformation of the interphase NE, together with the evidence for their potential roles in NR formation.
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Affiliation(s)
| | - David John Vaux
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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7
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Bader CA, Sorvina A, Simpson PV, Wright PJ, Stagni S, Plush SE, Massi M, Brooks DA. Imaging nuclear, endoplasmic reticulum and plasma membrane events in real time. FEBS Lett 2016; 590:3051-60. [DOI: 10.1002/1873-3468.12365] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/15/2016] [Accepted: 08/15/2016] [Indexed: 01/03/2023]
Affiliation(s)
- Christie A. Bader
- Mechanisms in Cell Biology and Disease Research Group School of Pharmacy and Medical Sciences Sansom Institute for Health Research University of South Australia Adelaide Australia
| | - Alexandra Sorvina
- Mechanisms in Cell Biology and Disease Research Group School of Pharmacy and Medical Sciences Sansom Institute for Health Research University of South Australia Adelaide Australia
| | - Peter V. Simpson
- Department of Chemistry and Nanochemistry Research Institute Curtin University Bently Australia
| | - Phillip J. Wright
- Department of Chemistry and Nanochemistry Research Institute Curtin University Bently Australia
| | - Stefano Stagni
- Department of Industrial Chemistry ‘Toso Montanari’ University of Bologna Italy
| | - Sally E. Plush
- Mechanisms in Cell Biology and Disease Research Group School of Pharmacy and Medical Sciences Sansom Institute for Health Research University of South Australia Adelaide Australia
| | - Massimiliano Massi
- Department of Chemistry and Nanochemistry Research Institute Curtin University Bently Australia
| | - Douglas A. Brooks
- Mechanisms in Cell Biology and Disease Research Group School of Pharmacy and Medical Sciences Sansom Institute for Health Research University of South Australia Adelaide Australia
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8
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Masuda M, Oshima A, Noguchi T, Kagiwada S. Induction of intranuclear membranes by overproduction of Opi1p and Scs2p, regulators for yeast phospholipid biosynthesis, suggests a mechanism for Opi1p nuclear translocation. J Biochem 2015; 159:351-61. [PMID: 26590299 DOI: 10.1093/jb/mvv105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/24/2015] [Indexed: 12/17/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, the expression of phospholipid biosynthetic genes is suppressed by the Opi1p negative regulator. Opi1p enters into the nucleoplasm from the nuclear membrane to suppress the gene expression under repressing conditions. The binding of Opi1p to the nuclear membrane requires an integral membrane protein, Scs2p and phosphatidic acid (PA). Although it is demonstrated that the association of Opi1p with membranes is affected by PA levels, how Opi1p dissociates from Scs2p is unknown. Here, we found that fluorescently labelled Opi1p accumulated on a perinuclear region in an Scs2p-dependent manner. Electron microscopic analyses indicated that the perinuclear region consists of intranuclear membranes, which may be formed by the invagination of the nuclear membrane due to the accumulation of Opi1p and Scs2p in a restricted area. As expected, localization of Opi1p and Scs2p in the intranuclear membranes was detected by immunoelectron microscopy. Biochemical analysis showed that Opi1p recovered in the membrane fraction was detergent insoluble while Scs2p was soluble, implying that Opi1p behaves differently from Scs2p in the fraction. We hypothesize that Opi1p dissociates from Scs2p after targeting to the nuclear membrane, making it possible to be released from the membrane quickly when PA levels decrease.
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Affiliation(s)
- Miki Masuda
- Department of Biological Sciences, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Ayaka Oshima
- Department of Biological Sciences, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Tetsuko Noguchi
- Department of Biological Sciences, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Satoshi Kagiwada
- Department of Biological Sciences, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
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9
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Timing the window of implantation by nucleolar channel system prevalence matches the accuracy of the endometrial receptivity array. Fertil Steril 2014; 102:1477-81. [DOI: 10.1016/j.fertnstert.2014.07.1254] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/28/2014] [Accepted: 07/30/2014] [Indexed: 01/31/2023]
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10
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Goto C, Tamura K, Fukao Y, Shimada T, Hara-Nishimura I. The Novel Nuclear Envelope Protein KAKU4 Modulates Nuclear Morphology in Arabidopsis. THE PLANT CELL 2014; 26:2143-2155. [PMID: 24824484 PMCID: PMC4079374 DOI: 10.1105/tpc.113.122168] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 04/16/2014] [Accepted: 04/23/2014] [Indexed: 05/18/2023]
Abstract
In animals, the nuclear lamina is a fibrillar meshwork on the inner surface of the nuclear envelope, composed of coiled-coil lamin proteins and lamin binding membrane proteins. Plants also have a meshwork on the inner surface of the nuclear envelope, but little is known about its composition other than the presence of members of the CROWDED NUCLEI (CRWN) protein family, possible plant lamin analogs. Here, we describe a candidate lamina component, based on two Arabidopsis thaliana mutants (kaku2 and kaku4) with aberrant nuclear morphology. The responsible gene in kaku2 encodes CRWN1, and the responsible gene in kaku4 encodes a plant-specific protein of unknown function (KAKU4) that physically interacts with CRWN1 and its homolog CRWN4. Immunogold labeling revealed that KAKU4 localizes at the inner nuclear membrane. KAKU4 deforms the nuclear envelope in a dose-dependent manner, in association with nuclear membrane invagination and stack formation. The KAKU4-dependent nuclear envelope deformation was enhanced by overaccumulation of CRWN1, although KAKU4 can deform the nuclear envelope even in the absence of CRWN1 and/or CRWN4. Together, these results suggest that plants have evolved a unique lamina-like structure to modulate nuclear shape and size.
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Affiliation(s)
- Chieko Goto
- Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kentaro Tamura
- Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yoichiro Fukao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | - Tomoo Shimada
- Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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11
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Goodwin EC, Motamedi N, Lipovsky A, Fernández-Busnadiego R, DiMaio D. Expression of DNAJB12 or DNAJB14 causes coordinate invasion of the nucleus by membranes associated with a novel nuclear pore structure. PLoS One 2014; 9:e94322. [PMID: 24732912 PMCID: PMC3986390 DOI: 10.1371/journal.pone.0094322] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/15/2014] [Indexed: 11/18/2022] Open
Abstract
DNAJB12 and DNAJB14 are transmembrane proteins in the endoplasmic reticulum (ER) that serve as co-chaperones for Hsc70/Hsp70 heat shock proteins. We demonstrate that over-expression of DNAJB12 or DNAJB14 causes the formation of elaborate membranous structures within cell nuclei, which we designate DJANGOS for DNAJ-associated nuclear globular structures. DJANGOS contain DNAJB12, DNAJB14, Hsc70 and markers of the ER lumen and ER and nuclear membranes. Strikingly, they are evenly distributed underneath the nuclear envelope and are of uniform size in any one nucleus. DJANGOS are composed primarily of single-walled membrane tubes and sheets that connect to the nuclear envelope via a unique configuration of membranes, in which the nuclear pore complex appears anchored exclusively to the outer nuclear membrane, allowing both the inner and outer nuclear membranes to flow past the circumference of the nuclear pore complex into the nucleus. DJANGOS break down rapidly during cell division and reform synchronously in the daughter cell nuclei, demonstrating that they are dynamic structures that undergo coordinate formation and dissolution. Genetic studies showed that the chaperone activity of DNAJ/Hsc70 is required for the formation of DJANGOS. Further analysis of these structures will provide insight into nuclear pore formation and function, activities of molecular chaperones, and mechanisms that maintain membrane identity.
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Affiliation(s)
- Edward C. Goodwin
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Nasim Motamedi
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Alex Lipovsky
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
| | | | - Daniel DiMaio
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics & Biochemistry, Yale School of Medicine, New Haven, Connecticut, United States of America
- Yale Cancer Center, New Haven, Connecticut, United States of America
- * E-mail:
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12
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Zapantis G, Szmyga M, Rybak E, Meier U. Premature formation of nucleolar channel systems indicates advanced endometrial maturation following controlled ovarian hyperstimulation. Hum Reprod 2013; 28:3292-300. [PMID: 24052503 PMCID: PMC3895983 DOI: 10.1093/humrep/det358] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/07/2013] [Accepted: 08/15/2013] [Indexed: 11/15/2022] Open
Abstract
STUDY QUESTION Is there a shift in the timing of nucleolar channel system (NCS) formation following controlled ovarian hyperstimulation (COH)? SUMMARY ANSWER NCSs appear prematurely following COH compared with natural cycles. WHAT IS KNOWN ALREADY During natural cycles, NCSs of endometrial epithelial cell (EEC) nuclei are exclusively present during the window of implantation and are uniformly distributed throughout the upper endometrial cavity. STUDY DESIGN, SIZE, DURATION Prospective two-cohort study. Cohorts I and II each consisted of seven volunteers for the duration of three menstrual study cycles that were separated by at least one wash-out or rest cycle, between December 2008 and May 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS Participants were recruited from a pool of healthy oocyte donors. Consecutive endometrial biopsies were obtained during the same luteal phase on cycle days (CD) 16, 20 and 26 for Cohort I, and on CD14, 22 and 24 for Cohort II, following random assignment to a natural cycle group, a COH cycle group (using a GnRH antagonist), or a COH cycle group receiving luteal phase hormonal supplementation (COH + S). The day of oocyte retrieval was designated CD14 in COH cycles and the day of the LH surge was designated CD13 in natural cycles. Prevalence of NCSs in the nuclei of EECs was quantified using indirect immunofluorescence with an antibody directed against a subset of related nuclear pore complex proteins that are major constituents of NCSs. Progesterone and estradiol levels were measured on the day of each endometrial biopsy. MAIN RESULTS AND THE ROLE OF CHANCE The natural cycle group exhibited peak NCS prevalence on CD20 [53.3%; interquartile range (IQR) 28.5-55.8], which rapidly declined on CD22 (11.8%; IQR 6.3-17.6), CD24 (2.5%; IQR 0.0-9.2) and CD26 (0.3%; IQR 0.0-3.5), and no NCSs on CD14 and 16 defining a short NCS window around CD20. In contrast, in COH and COH + S cycles, NCS prevalence was high already on CD16 (40.4%; IQR 22.6-53.4 and 35.6%; IQR 26.4-44.5, respectively; P = 0.001 compared with CD16 of the natural cycle group, Mann-Whitney), whereas no significant difference in NCS prevalence was detected on any of the other five CDs between the three groups (P > 0.05). LIMITATIONS, REASONS FOR CAUTION The cohort size was small (n = 7) but was offset by the all-or-none presence of NCSs on CD16 in natural versus COH and COH + S cycles and the fact that each subject served as her own control. WIDER IMPLICATIONS OF THE FINDINGS Premature appearance of NCSs and hence maturation of the endometrium following COH is consistent with previous studies based on histological dating but contradicts studies based on mRNA expression profiling, which reported a lag in endometrial maturation. However, this is the first study of this kind that is based on consecutive endometrial biopsies within the same cycle and that reports such clear-cut differences: no versus robust NCS presence on CD16. Our observation of advanced endometrial maturation following COH may contribute to the reduced implantation rates seen in fresh compared with frozen and donor IVF-embryo transfer cycles. Therefore, the NCS window could serve as a sensitive guide for timing of embryo transfer in frozen and donor cycles. STUDY FUNDING/COMPETING INTEREST(S) The study was supported by the March of Dimes Birth Defects foundation (1-FY09-363 to U.T.M.); Ferring Pharmaceuticals, Parsippany, NJ; East Coast Fertility, Plainview, NY and the CMBG Training Program (T32 GM007491 to M.J.S.). We report no competing interests.
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Affiliation(s)
- G. Zapantis
- Department of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- East Coast Fertility, Plainview, NY 11803, USA
- Present address: New York Reproductive Wellness, Jericho, NY 11753, USA
| | - M.J. Szmyga
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - E.A. Rybak
- Department of Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Present address: Reproductive Medicine Associates of New Jersey, Basking Ridge, NJ 07920, USA
| | - U.T. Meier
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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13
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Ring BA, Ferreira Lacerda A, Drummond DJ, Wangen C, Eaton HE, Brunetti CR. Frog virus 3 open reading frame 97R localizes to the endoplasmic reticulum and induces nuclear invaginations. J Virol 2013; 87:9199-207. [PMID: 23760249 PMCID: PMC3754063 DOI: 10.1128/jvi.00637-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 06/08/2013] [Indexed: 12/18/2022] Open
Abstract
Frog virus 3 (FV3) is the type species of the genus Ranavirus, family Iridoviridae. The genome of FV3 is 105,903 bases in length and encodes 97 open reading frames (ORFs). The FV3 ORF 97R contains a B-cell lymphoma 2 (Bcl-2) homology 1 (BH1) domain and has sequence similarity to the myeloid cell leukemia-1 (Mcl-1) protein, suggesting a potential role in apoptosis. To begin to understand the role of 97R, we characterized 97R through immunofluorescence and mutagenesis. Here we demonstrated that 97R localized to the endoplasmic reticulum (ER) at 24 h posttransfection. However, at 35 h posttransfection, 97R localized to the ER but also began to form concentrated pockets continuous with the nuclear membrane. After 48 h posttransfection, 97R was still localized to the ER, but we began to observe the ER and the outer nuclear membrane invaginating into the nucleus. To further explore 97R targeting to the ER, we created a series of C-terminal transmembrane domain deletion mutants. We found that deletion of 29 amino acids from the C terminus of 97R abolished localization to the ER. In contrast, deletion of 12 amino acids from the C terminus of 97R did not affect 97R localization to the ER. In addition, a hybrid protein containing the 97R C-terminal 33 amino acids was similarly targeted to the ER. These data indicate that the C-terminal 33 amino acids of 97R are necessary and sufficient for ER targeting.
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Affiliation(s)
- Brooke A Ring
- Department of Biology, Trent University, Peterborough, Ontario, Canada
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14
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Molecular aspects of implantation failure. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1943-50. [PMID: 22683339 DOI: 10.1016/j.bbadis.2012.05.017] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Accepted: 05/30/2012] [Indexed: 12/19/2022]
Abstract
Despite expanding global experience with advanced reproductive technologies, the majority of IVF attempts do not result in a successful pregnancy, foremost as a result of implantation failure. The process of embryo implantation, a remarkably dynamic and precisely controlled molecular and cellular event, appears inefficient in humans and is poorly understood. However, insights gained from clinical implantation failure, early pregnancy loss, and emerging techologies that enable molecular interrogation of endometrial-embryo interactions are unravelling this major limiting step in human reproduction. We review current molecular concepts thought to underlie implantation failure, consider the contribution of embryonic and endometrial factors, and discuss the clinical value of putative markers of impaired endometrial receptivity. Finally we highlight the nature of the dialogue between the maternal endometrium and the implanting embryo and discuss the concept of natural embryo selection. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.
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15
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Choi J. Oxidative stress, endogenous antioxidants, alcohol, and hepatitis C: pathogenic interactions and therapeutic considerations. Free Radic Biol Med 2012; 52:1135-50. [PMID: 22306508 DOI: 10.1016/j.freeradbiomed.2012.01.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 01/04/2012] [Accepted: 01/12/2012] [Indexed: 12/16/2022]
Abstract
Hepatitis C virus (HCV) is a blood-borne pathogen that was identified as an etiologic agent of non-A, non-B hepatitis in 1989. HCV is estimated to have infected at least 170 million people worldwide. The majority of patients infected with HCV do not clear the virus and become chronically infected, and chronic HCV infection increases the risk for hepatic steatosis, cirrhosis, and hepatocellular carcinoma. HCV induces oxidative/nitrosative stress from multiple sources, including inducible nitric oxide synthase, the mitochondrial electron transport chain, hepatocyte NAD(P)H oxidases, and inflammation, while decreasing glutathione. The cumulative oxidative burden is likely to promote both hepatic and extrahepatic conditions precipitated by HCV through a combination of local and more distal effects of reactive species, and clinical, animal, and in vitro studies strongly point to a role of oxidative/nitrosative stress in HCV-induced pathogenesis. Oxidative stress and hepatopathogenesis induced by HCV are exacerbated by even low doses of alcohol. Alcohol and reactive species may have other effects on hepatitis C patients such as modulation of the host immune system, viral replication, and positive selection of HCV sequence variants that contribute to antiviral resistance. This review summarizes the current understanding of redox interactions of HCV, outlining key experimental findings, directions for future research, and potential applications to therapy.
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Affiliation(s)
- Jinah Choi
- Department of Molecular Cell Biology, School of Natural Sciences, University of California at Merced, Merced, CA 95343, USA.
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16
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Malhas A, Goulbourne C, Vaux DJ. The nucleoplasmic reticulum: form and function. Trends Cell Biol 2011; 21:362-73. [DOI: 10.1016/j.tcb.2011.03.008] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/17/2011] [Accepted: 03/23/2011] [Indexed: 11/29/2022]
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17
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18
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de Mochel NSR, Seronello S, Wang SH, Ito C, Zheng JX, Liang TJ, Lambeth JD, Choi J. Hepatocyte NAD(P)H oxidases as an endogenous source of reactive oxygen species during hepatitis C virus infection. Hepatology 2010; 52:47-59. [PMID: 20578128 PMCID: PMC3141587 DOI: 10.1002/hep.23671] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
UNLABELLED Oxidative stress has been identified as a key mechanism of hepatitis C virus (HCV)-induced pathogenesis. Studies have suggested that HCV increases the generation of hydroxyl radical and peroxynitrite close to the cell nucleus, inflicting DNA damage, but the source of reactive oxygen species (ROS) remains incompletely characterized. We hypothesized that HCV increases the generation of superoxide and hydrogen peroxide close to the hepatocyte nucleus and that this source of ROS is reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase 4 (Nox4). Huh7 human hepatoma cells and telomerase-reconstituted primary human hepatocytes, transfected or infected with virus-producing HCV strains of genotypes 2a and 1b, were examined for messenger RNA (mRNA), protein, and subcellular localization of Nox proteins along with the human liver. We found that genotype 2a HCV induced persistent elevations of Nox1 and Nox4 mRNA and proteins in Huh7 cells. HCV genotype 1b likewise elevated the levels of Nox1 and Nox4 in telomerase-reconstituted primary human hepatocytes. Furthermore, Nox1 and Nox4 proteins were increased in HCV-infected human liver versus uninfected liver samples. Unlike Nox1, Nox4 was prominent in the nuclear compartment of these cells as well as the human liver, particularly in the presence of HCV. HCV-induced ROS and nuclear nitrotyrosine could be decreased with small interfering RNAs to Nox1 and Nox4. Finally, HCV increased the level of transforming growth factor beta 1 (TGFbeta1). TGFbeta1 could elevate Nox4 expression in the presence of infectious HCV, and HCV increased Nox4 at least in part through TGFbeta1. CONCLUSION HCV induced a persistent elevation of Nox1 and Nox4 and increased nuclear localization of Nox4 in hepatocytes in vitro and in the human liver. Hepatocyte Nox proteins are likely to act as a persistent, endogenous source of ROS during HCV-induced pathogenesis.
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Affiliation(s)
| | - Scott Seronello
- School of Natural Sciences, University of California, Merced, CA
| | | | - Chieri Ito
- School of Natural Sciences, University of California, Merced, CA
| | - Jasper Xi Zheng
- School of Natural Sciences, University of California, Merced, CA
| | - T. Jake Liang
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | | | - Jinah Choi
- School of Natural Sciences, University of California, Merced, CA,Contact Information: Jinah Choi, School of Natural Sciences, University of California, Merced, 5200 N. Lake Rd, Merced, CA 95343. Fax: 209-228-4060. Phone: 209-228-4386.
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19
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Linde N, Stick R. Intranuclear membranes induced by lipidated proteins are derived from the nuclear envelope. Nucleus 2010; 1:343-53. [PMID: 21327083 DOI: 10.4161/nucl.1.4.12352] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 04/22/2010] [Accepted: 04/28/2010] [Indexed: 01/12/2023] Open
Abstract
Association of nuclear lamins with the inner nuclear membrane (INM) is mediated by lipid modifications: either by C-terminal isoprenylation or N-terminal myristoylation. Overexpression of lamins or other lipidated nuclear proteins induces the formation of intranuclear membrane-like arrays. Lamin-induced intranuclear array formation has been observed in Xenopus oocytes as well as in mammalian tissue culture cells. With the use of a membrane-specific fluorescence dye we show here that these arrays are made up of typical lipid membranes. While continuity between these intranuclear membranes and the INM has not been observed so far the presence of integral as well as luminal marker proteins of the endoplasmic reticulum (ER) indicates that these membranes are derived from the nuclear membrane/ER compartment. Earlier studies demonstrated that overexpression of integral membrane proteins of the INM can induce formation of intranuclear membranes, which bud from the INM. Integral membrane proteins reach the INM via the pore membranes while lipidated proteins are imported into the nucleoplasm via the classical NLS pathway where they interact with the INM via their lipid moieties. Together with the previously published data our results show that the formation of intranuclear membranes follows similar routes irrespective of whether the proteins triggering membrane formation are integral membrane or lipidated proteins.
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Affiliation(s)
- Nina Linde
- Department of Cell Biology, University of Bremen, Bremen, Germany
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20
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Ilizarova NA, Marinkin IO, Ageeva TA, Bgatova NP, Kuleshov VM, Aidagulova SV. Ultrastructural and histochemical markers of endometrial secretion induction in habitual miscarriage. Bull Exp Biol Med 2010; 148:663-7. [PMID: 20396766 DOI: 10.1007/s10517-010-0790-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Biphasic hormone therapy at the stage of pre-gestation treatment of patients with habitual miscarriages stimulates the expression of progesterone receptors in the endometrium during the secretory phase of the menstrual cycle with full-value ultrastructural rearrangement of the endometrial glandular components in comparison with the patients receiving metabolic therapy alone.
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Affiliation(s)
- N A Ilizarova
- Institute of Regional Pathology and Pathomorphology, Siberian Division of the Russian Academy of Medical Sciences, Novosibirsk, Russia.
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21
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Carnemolla A, Fossale E, Agostoni E, Michelazzi S, Calligaris R, De Maso L, Del Sal G, MacDonald ME, Persichetti F. Rrs1 is involved in endoplasmic reticulum stress response in Huntington disease. J Biol Chem 2009; 284:18167-73. [PMID: 19433866 PMCID: PMC2709382 DOI: 10.1074/jbc.m109.018325] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 05/07/2009] [Indexed: 11/06/2022] Open
Abstract
The induction of Rrs1 expression is one of the earliest events detected in a presymptomatic knock-in mouse model of Huntington disease (HD). Rrs1 up-regulation fulfills the HD criteria of dominance, striatal specificity, and polyglutamine dependence. Here we show that mammalian Rrs1 is localized both in the nucleolus as well as in the endoplasmic reticulum (ER) of neurons. This dual localization is shared with its newly identified molecular partner 3D3/lyric. We then show that both genes are induced by ER stress in neurons. Interestingly, we demonstrate that ER stress is an early event in a presymptomatic HD mouse model that persists throughout the life span of the rodent. We further show that ER stress also occurs in postmortem brains of HD patients.
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Affiliation(s)
- Alisia Carnemolla
- From the Sector of Neurobiology, International School for Advanced Studies, Via Beirut 2-4, 34151 Trieste, Italy
| | - Elisa Fossale
- the Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Elena Agostoni
- From the Sector of Neurobiology, International School for Advanced Studies, Via Beirut 2-4, 34151 Trieste, Italy
| | - Silvia Michelazzi
- From the Sector of Neurobiology, International School for Advanced Studies, Via Beirut 2-4, 34151 Trieste, Italy
| | - Raffaella Calligaris
- From the Sector of Neurobiology, International School for Advanced Studies, Via Beirut 2-4, 34151 Trieste, Italy
| | - Luca De Maso
- From the Sector of Neurobiology, International School for Advanced Studies, Via Beirut 2-4, 34151 Trieste, Italy
| | - Giannino Del Sal
- the Laboratorio Nazionale CIB, Area Science Park Padriciano, 34149 Trieste, Italy, and
- the Dipartimento di Scienze della Vita, Universitá degli Studi di Trieste, Piazzale Europa 1, I-34127 Trieste, Italy
| | - Marcy E. MacDonald
- the Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Francesca Persichetti
- From the Sector of Neurobiology, International School for Advanced Studies, Via Beirut 2-4, 34151 Trieste, Italy
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22
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Guffanti E, Kittur N, Brodt ZN, Polotsky AJ, Kuokkanen SM, Heller DS, Young SL, Santoro N, Meier UT. Nuclear pore complex proteins mark the implantation window in human endometrium. J Cell Sci 2008; 121:2037-45. [PMID: 18505792 PMCID: PMC2657873 DOI: 10.1242/jcs.030437] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nucleolar channel systems (NCSs) are membranous organelles appearing transiently in the epithelial cell nuclei of postovulatory human endometrium. Their characterization and use as markers for a healthy receptive endometrium have been limited because they are only identifiable by electron microscopy. Here we describe the light microscopic detection of NCSs using immunofluorescence. Specifically, the monoclonal nuclear pore complex antibody 414 shows that NCSs are present in about half of all human endometrial epithelial cells but not in any other cell type, tissue or species. Most nuclei contain only a single NCS of uniform 1 microm diameter indicating a tightly controlled organelle. The composition of NCSs is as unique as their structure; they contain only a subset each of the proteins of nuclear pore complexes, inner nuclear membrane, nuclear lamina and endoplasmic reticulum. Validation of our robust NCS detection method on 95 endometrial biopsies defines a 6-day window, days 19-24 (+/-1) of an idealized 28 day cycle, wherein NCSs occur. Therefore, NCSs precede and overlap with the implantation window and serve as potential markers of uterine receptivity. The immunodetection assay, combined with the hitherto underappreciated prevalence of NCSs, now enables simple screening and further molecular and functional dissection.
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Affiliation(s)
- Elisa Guffanti
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Nupur Kittur
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Z. Nilly Brodt
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Alex J. Polotsky
- Department of Obstetrics, Gynecology and Women's Health, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Satu M. Kuokkanen
- Department of Obstetrics, Gynecology and Women's Health, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Debra S. Heller
- Department of Pathology, UMDNJ – New Jersey Medical School, Newark, NJ 07101, USA
| | - Steven L. Young
- Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Nanette Santoro
- Department of Obstetrics, Gynecology and Women's Health, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - U. Thomas Meier
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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23
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Savard M, Barbaz D, Bélanger S, Müller-Esterl W, Bkaily G, D'orléans-Juste P, Coté J, Bovenzi V, Gobeil F. Expression of endogenous nuclear bradykinin B2 receptors mediating signaling in immediate early gene activation. J Cell Physiol 2008; 216:234-44. [PMID: 18264983 DOI: 10.1002/jcp.21398] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Bradykinin (BK) represents a pro-inflammatory mediator that partakes in many inflammatory diseases. The mechanism of action of BK is thought to be primarily mediated by specific cell surface membrane B2 receptors (B2Rs). Some evidence has suggested, however, the existence of an intracellular/nuclear B2R population. Whether these receptors are functional and contribute to BK signaling remains to be determined. In this study, by mean of Western blotting, 3D-confocal microscopy, receptor autoradiography and radioligand binding analysis, we showed that plasma membrane and highly purified nuclei from isolated rat hepatocytes contain specific B2R that bind BK. The results depicting B2R nuclear expression in isolated nuclear organelles were reproduced in situ on hepatic sections by immunogold labeling and transmission electron microscopy. Functional tests on single nuclei, by means of confocal microscopy and the calcium-sensitive probe fluo-4AM, showed that BK induces concentration-dependent transitory mobilization of nucleoplasmic calcium; these responses were blocked by B2R antagonist HOE 140, not by the B1R antagonist R954 and, were also found in wild-type C57/Bl6 mice, but not in B2R-KO mice. In isolated nuclei, BK elicited activation/phosphorylation of Akt, acetylation of histone H3 and ensuing pro-inflammatory iNOS gene induction as determined by Western blot and RT-PCR. ChIP assay confirmed binding of acetylated-histone H3 complexes, but not B2R, to promoter region of iNOS gene suggesting that B2R-mediated gene expression is bridged with accessory downstream effectors. This study discloses a previously undescribed mechanism in BK-induced transcriptional events, via intracrine B2R-mediated signaling, occurring in rat autologous hepatic cells.
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Affiliation(s)
- Martin Savard
- Department of Pharmacology, Université de Sherbrooke, Sherbrooke, Québec, Canada
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24
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Gehrig K, Cornell RB, Ridgway ND. Expansion of the nucleoplasmic reticulum requires the coordinated activity of lamins and CTP:phosphocholine cytidylyltransferase alpha. Mol Biol Cell 2007; 19:237-47. [PMID: 17959832 DOI: 10.1091/mbc.e07-02-0179] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The nucleoplasmic reticulum (NR), a nuclear membrane network implicated in signaling and transport, is formed by the biosynthetic and membrane curvature-inducing properties of the rate-limiting enzyme in phosphatidylcholine synthesis, CTP:phosphocholine cytidylyltransferase (CCT) alpha. The NR is formed by invagination of the nuclear envelope and has an underlying lamina that may contribute to membrane tubule formation or stability. In this study we investigated the role of lamins A and B in NR formation in response to expression and activation of endogenous and fluorescent protein-tagged CCTalpha. Similarly to endogenous CCTalpha, CCT-green fluorescent protein (GFP) reversibly translocated to nuclear tubules projecting from the NE in response to oleate, a lipid promoter of CCT membrane binding. Coexpression and RNA interference experiments revealed that both CCTalpha and lamin A and B were necessary for NR proliferation. Expression of CCT-GFP mutants with compromised membrane-binding affinity produced fewer nuclear tubules, indicating that the membrane-binding function of CCTalpha promotes the expansion of the NR. Proliferation of atypical bundles of nuclear membrane tubules by a CCTalpha mutant that constitutively associated with membranes revealed that expansion of the double-bilayer NR requires the coordinated assembly of an underlying lamin scaffold and induction of membrane curvature by CCTalpha.
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Affiliation(s)
- Karsten Gehrig
- *Departments of Pediatrics, and Biochemistry and Molecular Biology, Atlantic Research Centre, Dalhousie University, Halifax, NS, Canada B3H 4H7
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25
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Diedrich K, Fauser BCJM, Devroey P, Griesinger G. The role of the endometrium and embryo in human implantation. Hum Reprod Update 2007; 13:365-77. [PMID: 17548368 DOI: 10.1093/humupd/dmm011] [Citation(s) in RCA: 198] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite many advances in assisted reproductive technologies (ART), implantation rates are still low. The process of implantation requires a reciprocal interaction between blastocyst and endometrium, culminating in a small window of opportunity during which implantation can occur. This interaction involves the embryo, with its inherent molecular programme of cell growth and differentiation, and the temporal differentiation of endometrial cells to attain uterine receptivity. Implantation itself is governed by an array of endocrine, paracrine and autocrine modulators, of embryonic and maternal origin. Implantation failure is thought to occur as a consequence of impairment of embryo developmental potential and/or impairment of uterine receptivity and the embryo-uterine dialogue. Therefore a better comprehension of implantation, and the relative importance of the factors involved, is warranted. New techniques for monitoring changes in the endometrium and/or the embryo at the level of gene regulation and protein expression may lead to the identification of better markers for implantation. Moreover, the use of predictive sets of markers may prove to be more reliable than a single marker. Continuing refinements to ART protocols, such as optimizing ovarian stimulation regimens, the timing of human chorionic gonadotrophin injection, or the timing of embryo transfer, should help to increase implantation rates further.
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Affiliation(s)
- K Diedrich
- Department of Obstetrics and Gynecology, University Hospital Schleswig-Holstein, Campus Lübeck, 23538 Luebeck, Germany
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26
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Kittur N, Zapantis G, Aubuchon M, Santoro N, Bazett-Jones DP, Meier UT. The nucleolar channel system of human endometrium is related to endoplasmic reticulum and R-rings. Mol Biol Cell 2007; 18:2296-304. [PMID: 17429075 PMCID: PMC1877118 DOI: 10.1091/mbc.e07-02-0154] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 04/02/2007] [Indexed: 11/11/2022] Open
Abstract
The nucleolar channel system (NCS) is a well-established ultrastructural hallmark of the postovulation endometrium. Its transient presence has been associated with human fertility. Nevertheless, the biogenesis, composition, and function of these intranuclear membrane cisternae are unknown. Membrane systems with a striking ultrastructural resemblance to the NCS, termed R-rings, are induced in nuclei of tissue culture cells by overexpression of the central repeat domain of the nucleolar protein Nopp140. Here we provide a first molecular characterization of the NCS and compare the biogenesis of these two enigmatic organelles. Like the R-rings, the NCS consists of endoplasmic reticulum harboring the marker glucose-6-phosphatase. R-ring formation initiates at the nuclear envelope, apparently by a calcium-mediated Nopp140-membrane interaction, as supported by the calcium-binding ability of Nopp140, the inhibition of R-ring formation by calcium chelators, and the concentration of Nopp140 and complexed calcium in R-rings. Although biogenesis of the NCS may initiate similarly, the reduced presence of complexed calcium and Nopp140 suggests the involvement of additional factors.
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Affiliation(s)
- Nupur Kittur
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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27
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Deng M, Hochstrasser M. Spatially regulated ubiquitin ligation by an ER/nuclear membrane ligase. Nature 2006; 443:827-31. [PMID: 17051211 DOI: 10.1038/nature05170] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Accepted: 08/15/2006] [Indexed: 11/09/2022]
Abstract
The ubiquitin system targets many cellular proteins. Doa10 (also known as Ssm4), a yeast transmembrane ubiquitin ligase (E3), resides in the endoplasmic reticulum (ER), but it attaches ubiquitin to soluble proteins that concentrate in the nucleus. A central question is how nuclear substrates gain access to an enzyme in the ER. Here we show that Doa10 reaches the inner nuclear membrane. A subcomplex of nuclear pore subunits is important for this transport. Notably, another ER transmembrane E3, Hrd1 (also known as Der3), cannot localize efficiently to the inner nuclear membrane. Tethering Doa10 at the cell periphery inhibits degradation of soluble nuclear substrates but not cytoplasmic ones. If Doa10 is released from these peripheral sites, localization of Doa10 to the nuclear envelope and degradation of its nuclear substrates are restored in parallel. Thus, localization of Doa10 to the inner nuclear membrane is necessary for nuclear substrate degradation. These data indicate that different membrane ubiquitin ligases are spatially sorted within the ER-nuclear envelope membrane system and that this differential localization contributes to their specificity.
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Affiliation(s)
- Min Deng
- Yale University, Department of Molecular Biophysics and Biochemistry, 266 Whitney Avenue, P.O. Box 208114, New Haven, Connecticut 06520-8114, USA
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28
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Gobeil F, Fortier A, Zhu T, Bossolasco M, Leduc M, Grandbois M, Heveker N, Bkaily G, Chemtob S, Barbaz D. G-protein-coupled receptors signalling at the cell nucleus: an emerging paradigm. Can J Physiol Pharmacol 2006; 84:287-97. [PMID: 16902576 DOI: 10.1139/y05-127] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
G-protein-coupled receptors (GPCRs) comprise a wide family of monomeric heptahelical glycoproteins that recognize a broad array of extracellular mediators including cationic amines, lipids, peptides, proteins, and sensory agents. Thus far, much attention has been given towards the comprehension of intracellular signaling mechanisms activated by cell membrane GPCRs, which convert extracellular hormonal stimuli into acute, non-genomic (e.g., hormone secretion, muscle contraction, and cell metabolism) and delayed, genomic biological responses (e.g., cell division, proliferation, and apoptosis). However, with respect to the latter response, there is compelling evidence for a novel intracrine mode of genomic regulation by GPCRs that implies either the endocytosis and nuclear translocation of peripheral-liganded GPCR and (or) the activation of nuclearly located GPCR by endogenously produced, nonsecreted ligands. A noteworthy example of the last scenario is given by heptahelical receptors that are activated by bioactive lipoids (e.g., PGE(2) and PAF), many of which may be formed from bilayer membranes including those of the nucleus. The experimental evidence for the nuclear localization and signalling of GPCRs will be reviewed. We will also discuss possible molecular mechanisms responsible for the atypical compartmentalization of GPCRs at the cell nucleus, along with their role in gene expression.
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Affiliation(s)
- Fernand Gobeil
- Department of Pharmacology, Faculty of Medicine, Université de Sherbrooke, Fleurimont, Canada.
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29
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Zhu T, Gobeil F, Vazquez-Tello A, Leduc M, Rihakova L, Bossolasco M, Bkaily G, Peri K, Varma DR, Orvoine R, Chemtob S. Intracrine signaling through lipid mediators and their cognate nuclear G-protein-coupled receptors: a paradigm based on PGE2, PAF, and LPA1 receptors. Can J Physiol Pharmacol 2006; 84:377-91. [PMID: 16902584 DOI: 10.1139/y05-147] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Prostaglandins (PGs), platelet-activating factor (PAF), and lysophosphatidic acid (LPA) are ubiquitous lipid mediators that play important roles in inflammation, cardiovascular homeostasis, and immunity and are also known to modulate gene expression of specific pro-inflammatory genes. The mechanism of action of these lipids is thought to be primarily dependent on their specific plasma membrane receptors belonging to the superfamily of G-protein-coupled receptors (GPCR). Increasing evidence suggests the existence of a functional intracellular GPCR population. It has been proposed that immediate effects are mediated via cell surface receptors whereas long-term responses are dependent upon intracellular receptor effects. Indeed, receptors for PAF, LPA, and PGE(2) (specifically EP(1), EP(3), and EP(4)) localize at the cell nucleus of cerebral microvascular endothelial cells of newborn pigs, rat hepatocytes, and cells overexpressing each receptor. Stimulation of isolated nuclei with these lipids reveals biological functions including transcriptional regulation of major genes, namely c-fos, cylooxygenase-2, and endothelial as well as inducible nitric oxide synthase. In the present review, we shall focus on the nuclear localization and signaling of GPCRs recognizing PGE(2), PAF, and LPA phospholipids as ligands. Mechanisms on how nuclear PGE2, PAF, and LPA receptors activate gene transcription and nuclear localization pathways are presented. Intracrine signaling for lipid mediators uncover novel pathways to elicit their effects; accordingly, intracellular GPCRs constitute a distinctive mode of action for gene regulation.
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Affiliation(s)
- Tang Zhu
- Department of Pediatrics, Research Center of Hôpital Sainte-Justine, Université de Montréal, QC, Canada
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30
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Kuroda J, Nakagawa K, Yamasaki T, Nakamura KI, Takeya R, Kuribayashi F, Imajoh-Ohmi S, Igarashi K, Shibata Y, Sueishi K, Sumimoto H. The superoxide-producing NAD(P)H oxidase Nox4 in the nucleus of human vascular endothelial cells. Genes Cells 2006; 10:1139-51. [PMID: 16324151 DOI: 10.1111/j.1365-2443.2005.00907.x] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The superoxide-producing NAD(P)H oxidase Nox4 was initially identified as an enzyme that is highly expressed in the kidney and is possibly involved in oxygen sensing and cellular senescence. Although the oxidase is also abundant in vascular endothelial cells, its role remains to be elucidated. Here we show that Nox4 preferentially localizes to the nucleus of human umbilical vein endothelial cells (HUVECs), by immunocytochemistry and immunoelectron microscopy using three kinds of affinity-purified antibodies raised against distinct immunogens from human Nox4. Silencing of Nox4 by RNA interference (RNAi) abrogates nuclear signals given with the antibodies, confirming the nuclear localization of Nox4. The nuclear fraction of HUVECs exhibits an NAD(P)H-dependent superoxide-producing activity in a manner dependent on Nox4, which activity can be enhanced upon cell stimulation with phorbol 12-myristate 13-acetate. This stimulant also facilitates gene expression as estimated in the present transfection assay of HUVECs using a reporter regulated by the Maf-recognition element MARE, a DNA sequence that constitutes a part of oxidative stress response. Both basal and stimulated transcriptional activities are impaired by RNAi-mediated Nox4 silencing. Thus Nox4 appears to produce superoxide in the nucleus of HUVECs, thereby regulating gene expression via a mechanism for oxidative stress response.
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Affiliation(s)
- Junya Kuroda
- Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka, Japan
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31
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de Roos ADG. The origin of the eukaryotic cell based on conservation of existing interfaces. ARTIFICIAL LIFE 2006; 12:513-23. [PMID: 16953783 DOI: 10.1162/artl.2006.12.4.513] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Current theories about the origin of the eukaryotic cell all assume that during evolution a prokaryotic cell acquired a nucleus. Here, it is shown that a scenario in which the nucleus acquired a plasma membrane is inherently less complex because existing interfaces remain intact during evolution. Using this scenario, the evolution to the first eukaryotic cell can be modeled in three steps, based on the self-assembly of cellular membranes by lipid-protein interactions. First, the inclusion of chromosomes in a nuclear membrane is mediated by interactions between laminar proteins and lipid vesicles. Second, the formation of a primitive endoplasmic reticulum, or exomembrane, is induced by the expression of intrinsic membrane proteins. Third, a plasma membrane is formed by fusion of exomembrane vesicles on the cytoskeletal protein scaffold. All three self-assembly processes occur both in vivo and in vitro. This new model provides a gradual Darwinistic evolutionary model of the origins of the eukaryotic cell and suggests an inherent ability of an ancestral, primitive genome to induce its own inclusion in a membrane.
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Affiliation(s)
- Albert D G de Roos
- The Beagle Armada, Bioinformatics Division, Einsteinstraat 67, 3316GG Dordrecht, The Netherlands.
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Marrache AM, Gobeil F, Zhu T, Chemtob S. Intracellular signaling of lipid mediators via cognate nuclear G protein-coupled receptors. ACTA ACUST UNITED AC 2005; 12:63-72. [PMID: 16036317 DOI: 10.1080/10623320590933815] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Platelet-activating factor (PAF) and lysophosphatidic acid (LPA) are ubiquitous lipid mediators that play important roles in inflammation, cardiovascular homeostasis, and immunity and are also known to modulate gene expression of specific proinflammatory genes. The mechanism of action of these phospholipids is thought to be primarily dependent on their specific plasma membrane receptors belonging to the superfamily of G protein-coupled receptors (GPCRs). However, increasing evidence suggests the existence of a functional intracellular GPCR population. It has been suggested that immediate effects are mediated by cell surface receptors, whereas long-term responses are mediated by intracellular receptors. PAF and LPA(1) receptors localize at the cell nucleus of cerebral microvascular endothelial cells of newborn pig, rat hepatocytes, and cells overexpressing each receptor, and stimulation of isolated nuclei reveal biological functions, including transcriptional regulation of major genes, namely cylooxygenase-2 and inducible nitric oxide synthase. This mini review focuses on the nuclear localization and signaling of GPCRs, recognizing PAF and LPA phospholipids as ligands. Theories on how nuclear PAF and LPA1 receptors activate gene transcription and nuclear localization pathways are discussed. Intracrine signaling for lipid mediators uncover novel pathways to elicit their effects; moreover, intracellular GPCRs constitute a distinctive mode of action for gene regulation.
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33
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Prüfert K, Alsheimer M, Benavente R, Krohne G. The myristoylation site of meiotic lamin C2 promotes local nuclear membrane growth and the formation of intranuclear membranes in somatic cultured cells. Eur J Cell Biol 2005; 84:637-46. [PMID: 16032931 DOI: 10.1016/j.ejcb.2004.12.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Lamin C2 is a splice product of the mammalian lamin A gene and expressed in primary spermatocytes where it is distributed in the form of discontinuous plaques at the nuclear envelope. We have previously shown that the aminoterminal hexapetide GNAEGR of lamin C2 following the start methionine is essential for its association with the nuclear envelope and that the aminoterminal glycine of the hexapeptide is myristoylated. Here we have analyzed the ultrastructural changes induced in COS-7 and Xenopus A6 cells by overexpressing rat lamin C2 or a human lamin C mutant possessing the lamin C2-specific hexapeptide at its aminoterminus. Both lamins were targeted to the nuclear envelope of mammalian and amphibian cells and induced the formation of intranuclear membranes, whereas wild-type human lamin C and a lamin C2 mutant, that both lack this lipid moiety, did not. Our data indicate that the myristoyl group of lamin C2 has besides its demonstrated role in nuclear envelope association additional functions during spermatogenesis. Our present study complements previously published results where we have shown that the CxxM motif of lamins promotes nuclear membrane growth (Prüfert et al., 2004. J. Cell Sci. 117, 6105-6116).
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Affiliation(s)
- Kristina Prüfert
- Division of Electron Microscopy, Biocenter of the University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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34
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Meier UT. The many facets of H/ACA ribonucleoproteins. Chromosoma 2005; 114:1-14. [PMID: 15770508 PMCID: PMC4313906 DOI: 10.1007/s00412-005-0333-9] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 01/31/2005] [Accepted: 02/01/2005] [Indexed: 10/25/2022]
Abstract
The H/ACA ribonucleoproteins (RNPs) are known as one of the two major classes of small nucleolar RNPs. They predominantly guide the site-directed pseudouridylation of target RNAs, such as ribosomal and spliceosomal small nuclear RNAs. In addition, they process ribosomal RNA and stabilize vertebrate telomerase RNA. Taken together, the function of H/ACA RNPs is essential for ribosome biogenesis, pre-mRNA splicing, and telomere maintenance. Every cell contains 100-200 different species of H/ACA RNPs, each consisting of the same four core proteins and one function-specifying H/ACA RNA. Most of these RNPs reside in nucleoli and Cajal bodies and mediate the isomerization of specific uridines to pseudouridines. Catalysis of the reaction is mediated by the putative pseudouridylase NAP57 (dyskerin, Cbf5p). Unexpectedly, mutations in this housekeeping enzyme are the major determinants of the inherited bone marrow failure syndrome dyskeratosis congenita. This review details the many diverse functions of H/ACA RNPs, some yet to be uncovered, with an emphasis on the role of the RNP proteins. The multiple functions of H/ACA RNPs appear to be reflected in the complex phenotype of dyskeratosis congenita.
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Affiliation(s)
- U Thomas Meier
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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35
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Abstract
We analyzed the influence of lamins on nuclear envelope growth in cultured Xenopus A6 cells by the overexpression of human lamin A, Xenopus and zebrafish lamins B2 and Drosophila lamins Dm0 and C as GFP fusion proteins. Lamins containing a CxxM motif in their primary sequence (lamins A, B2, Dm0) induced the formation of lobulated nuclei with multi-membrane-layered, highly folded nuclear membranes and intranuclear membrane assemblies, as observed by electron microscopy. Such morphological alterations were not observed with Drosophila lamin C, a lamin without this motif or with a lamin B2 mutant (B2-SxxM) where the cysteine of the CxxM motif is replaced by a serine. Drosophila lamin C mutants containing a CxxM motif behaved like B-type lamins thus confirming that this tetrapeptide is directly involved in the morphological changes we observed. Nuclear membrane proliferation could also be induced by lamin B2 in COS-7 cells and in zebrafish embryos but not by human lamin A in COS-7 cells. We speculate that the human lamin A is incompletely processed in Xenopus A6 cells and therefore behaves in this cell line like a B-type lamin. Our results indicate that the CxxM motif of B-type lamins has a dual function: it mediates lamin targeting to the inner nuclear membrane thereby promoting nuclear membrane growth.
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Affiliation(s)
- Kristina Prüfert
- Division of Electron Microscopy, Biocenter of the University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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36
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Sutherland HGE, Lam YW, Briers S, Lamond AI, Bickmore WA. 3D3/lyric: a novel transmembrane protein of the endoplasmic reticulum and nuclear envelope, which is also present in the nucleolus. Exp Cell Res 2004; 294:94-105. [PMID: 14980505 DOI: 10.1016/j.yexcr.2003.11.020] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Indexed: 11/26/2022]
Abstract
We previously performed a gene-trap screen in mouse cells with particular focus on clones in which the trapped protein-reporter fusions localise to compartments of the nucleus. Here we describe one such gene-trap line in which the fusion protein showed a unique, patchy distribution at the nuclear periphery. We have cloned the endogenous mouse and human cDNAs encoding the protein trapped in the F9/3D3 cell line. The predicted proteins (64 kDa) encoded by this novel gene are highly conserved and similar to an unpublished rat protein in sequence databases called p80 or lyric. The amino acid sequence of 3D3/lyric indicates that it may be a type-1b membrane protein with a single transmembrane domain (TMD). Antibodies against the endogenous protein recognise multiple isoforms, consistent with multiple 3D3/lyric mRNAs detected by Northern blot analysis. Subcellular fractionation and immunostaining show that 3D3/lyric is located not only principally in the endoplasmic reticulum (ER), but also in the nuclear envelope (NE), which is contiguous with this compartment. Furthermore, 3D3/lyric is also found in the nucleolus and is therefore a rare example of a protein that suggests a possible connection between this compartment and the endoplasmic reticulum.
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Sørensen V, Brech A, Khnykin D, Kolpakova E, Citores L, Olsnes S. Deletion mutant of FGFR4 induces onion-like membrane structures in the nucleus. J Cell Sci 2004; 117:1807-19. [PMID: 15075241 DOI: 10.1242/jcs.01047] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of several deletion mutants of fibroblast growth factor receptor 4 (FGFR4) was studied in COS-1 cells. FGFR4-mutants lacking most of the extracellular region did not efficiently reach the plasma membrane but accumulated in the endoplasmic reticulum (ER) and Golgi body. A mutant FGFR4 lacking the kinase domain as well as most of the extracellular region (DeltaExt/R4Tth) had a distinct intracellular distribution. It localized in part to the nucleus, where it exhibited a striking spotted pattern. Ultrastructural studies showed that the nuclear spots consisted of several layers of membrane that were folded into onion-like structures at the nucleoplasmic side of the nuclear envelope. These intranuclear structures did not contain nuclear pores but were positive for the ER proteins calreticulin and protein disulfide isomerase, in addition to abundant DeltaExt/R4Tth. Formation of the intranuclear structures was sensitive to inhibition of protein kinase C. Live microscopy of a green-fluorescent-protein/DeltaExt/R4Tth fusion protein showed that the intranuclear structures were stable and immobile, suggesting that they function as deposits of the overexpressed mutant and associated membrane. The DeltaExt/R4Tth protein also induced formation of densely packed membrane stacks in the cytosol and we suggest a model were the intranuclear structures are formed by invagination of ER-derived membrane stacks into the nucleus.
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Affiliation(s)
- Vigdis Sørensen
- Institute for Cancer Research, The Norwegian Radium Hospital, Department of Biochemistry, Montebello, 0310 Oslo, Norway
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Devroey P, Bourgain C, Macklon NS, Fauser BCJM. Reproductive biology and IVF: ovarian stimulation and endometrial receptivity. Trends Endocrinol Metab 2004; 15:84-90. [PMID: 15036255 DOI: 10.1016/j.tem.2004.01.009] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The influence of ovarian stimulation on endometrium receptivity has been inadequately addressed in medical literature. Hormonal effects of ovarian stimulation on endometrial changes as compared with the natural cycle should be elucidated and correlated with the potential of the embryo to implant. It is important to distinguish between the endometrial effect of induction of ovulation in anovulatory women and those of ovarian (super)ovulation in ovulatory women. Induction of ovulation leads to in vivo conception whereas ovarian stimulation results in in vitro fertilization. The available data in the field indicate that endometrial changes have an impressive negative influence on the potential of embryonic implantation. The aim of this review is to analyse the effects of gonadotropin, GnRH-agonist and GnRH-antagonist administration on endometrial behaviour, to highlight the gaps in current knowledge and to propose areas in which research is needed.
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Affiliation(s)
- Paul Devroey
- Centre for Reproductive Medicine, University Hospital, Dutch-speaking Brussels Free University (Vrije Universiteit Brussel), Laarbeeklaan 101, 1090 Brussels, Belgium.
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Abstract
The histological changes underwent by endometrium during a natural menstrual cycle were described more than 50 years ago. Dating yields several methodological flaws, with intra- and inter-observer variability and shows questionable relationship to endometrial receptivity. The best studied endometrial factors involved in implantation include the formation of luminal epithelial "pinopodes", expression of adhesion molecules and of cytokines. Ovarian stimulation for IVF is known to affect luteal phase function. Factors influencing the endometrial receptivity in such cycles are poorly understood. Studies comparing the endometrium in IVF cycles with natural cycle controls have shown premature secretory changes in the postovulatory and early luteal phase of IVF cycles. These findings suggest a profound modification of luteal endometrial development in stimulated cycles. Studies exploring the endometrium within the cycle of embryo transfer have shown a deleterious effect of severe periovulatory maturation advancement exceeding 3 days, as no clinical pregnancies were observed in this condition.
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Affiliation(s)
- C Bourgain
- Laboratoire d'anatomopathologie, Centre de Médecine de la Reproduction, Bruxelles, Belgique
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Sekiguchi T, Todaka Y, Wang Y, Hirose E, Nakashima N, Nishimoto T. A novel human nucleolar protein, Nop132, binds to the G proteins, RRAG A/C/D. J Biol Chem 2003; 279:8343-50. [PMID: 14660641 DOI: 10.1074/jbc.m305935200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RRAG A (Rag A)/Gtr1p is a member of the Ras-like small G protein family that genetically interacts with RCC1, a guanine nucleotide exchange factor for RanGTPase. RRAG A/Gtr1p forms a heterodimer with other G proteins, RRAG C and RRAG D/Gtr2p, in a nucleotide-independent manner. To further elucidate the function of RRAG A/Gtr1p, we isolated a protein that interacts with RRAG A. This protein is a novel nucleolar protein, Nop132. Nop132 is associated with the GTP form, but not the GDP form, of RRAG A, suggesting that RRAG A might regulate Nop132 function. Nop132 is also associated with RRAG C and RRAG D. The Nop132 amino acid sequence is similar to the Saccharomyces cerevisiae nucleolar Nop8p, which is associated with Gtr1p, Gtr2p, and Nip7p. Nop132 also interacts with human Nip7 and is colocalized with RRAG A, RRAG C, and Nip7. RNA interference knockdown of Nop132 inhibited cell growth of HeLa cells.
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Affiliation(s)
- Takeshi Sekiguchi
- Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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Kim YK, Jin Y, Vukoti KM, Park JK, Kim EE, Lee KJ, Yu YG. Purification and characterization of human nucleolar phosphoprotein 140 expressed in Escherichia coli. Protein Expr Purif 2003; 31:260-4. [PMID: 14550645 DOI: 10.1016/s1046-5928(03)00194-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Human nucleolar phosphoprotein 140, hNopp140, is one of the most highly phosphorylated mammalian proteins, which is involved in the biogenesis of nucleolus. It regulates the transcription of rDNA and has a tendency to bind to doxorubicin, which is widely used as an anti-cancer drug. The biochemical and biophysical property of hNopp140 has not been reported due to the fact that it is rather difficult to obtain protein in large enough quantity. In this paper, we report the cloning and overexpression of the soluble form of hNopp140 in Escherichia coli. The protein was purified to more than 90% homogeneity using hydroxyapatite and ion exchange chromatography. The purified protein can be extensively phosphorylated by casein kinase II and oligomerized into an insoluble aggregate in the presence of magnesium, carbonate, and fluoride ions.
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Affiliation(s)
- Yun-Kyeong Kim
- Division of Life Sciences, Korea Institute of Science and Technology, 39-1, Hwawolkok-dong, Songbuk-ku, 136-791 Seoul, South Korea
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42
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Chiu CM, Tsay YG, Chang CJ, Lee SC. Nopp140 is a mediator of the protein kinase A signaling pathway that activates the acute phase response alpha1-acid glycoprotein gene. J Biol Chem 2002; 277:39102-11. [PMID: 12167624 DOI: 10.1074/jbc.m205915200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The acute phase response (APR) in liver during inflammation is one of the well known examples for elucidating the signaling pathways that lead to the combinatorial regulation of gene expression. The APR is exemplified by alpha(1)-acid glycoprotein gene (agp) expression. A number of transcription factors, including CCAAT/enhancer-binding protein beta (C/EBPbeta), glucocorticoid receptor, cAMP-response element-binding protein (CREB), and Nopp140, are known to participate in its induction. The underlying mechanism of Nopp140 and other factors for regulating agp expression remains unclear. Here we demonstrate that protein kinase A (PKA)-dependent phosphorylation of Nopp140, together with C/EBPbeta, induces agp gene expression synergistically. The cooperative activation of the agp gene by Nopp140 and forskolin is sensitive to inhibition by PKI. Results from biochemical and functional characterizations of Nopp140 mutants defective in PKA phosphorylation sites suggest that PKA-dependent Nopp140 phosphorylation is important for its role in agp gene activation. Furthermore, maximal activation of the agp gene by PKA-phosphorylated Nopp140 depends on the presence of CREB and C/EBPbeta. The participation of CREB in the activation is, however, independent of its PKA-mediated phosphorylation. In summary, we demonstrate the existence of a novel Nopp140-mediated PKA signaling pathway that leads to the activation of agp, one of the major acute phase response genes.
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Affiliation(s)
- Chi-Ming Chiu
- Institute of Molecular Medicine and Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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