51
|
Lattanzi G, Columbaro M, Mattioli E, Cenni V, Camozzi D, Wehnert M, Santi S, Riccio M, Del Coco R, Maraldi NM, Squarzoni S, Foisner R, Capanni C. Pre-Lamin A processing is linked to heterochromatin organization. J Cell Biochem 2007; 102:1149-59. [PMID: 17654502 DOI: 10.1002/jcb.21467] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pre-lamin A undergoes subsequent steps of post-translational modification at its C-terminus, including farnesylation, methylation, and cleavage by ZMPSTE24 metalloprotease. Here, we show that accumulation of different intermediates of pre-lamin A processing in nuclei, induced by expression of mutated pre-lamin A, differentially affected chromatin organization in human fibroblasts. Unprocessed (non-farnesylated) pre-lamin A accumulated in intranuclear foci, caused the redistribution of LAP2alpha and of the heterochromatin markers HP1alpha and trimethyl-K9-histone 3, and triggered heterochromatin localization in the nuclear interior. In contrast, the farnesylated and carboxymethylated lamin A precursor accumulated at the nuclear periphery and caused loss of heterochromatin markers and Lap2alpha in enlarged nuclei. Interestingly, pre-lamin A bound both HP1alpha and LAP2alpha in vivo, but the farnesylated form showed reduced affinity for HP1alpha. Our data show a link between pre-lamin A processing and heterochromatin remodeling and have major implications for understanding molecular mechanisms of human diseases linked to mutations in lamins.
Collapse
|
52
|
Mattout A, Goldberg M, Tzur Y, Margalit A, Gruenbaum Y. Specific and conserved sequences in D. melanogaster and C. elegans lamins and histone H2A mediate the attachment of lamins to chromosomes. J Cell Sci 2006; 120:77-85. [PMID: 17148572 DOI: 10.1242/jcs.03325] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The intimate association between nuclear lamins and chromatin is thought to regulate higher order chromatin organization. Previous studies have mapped a region between the rod domain and the Ig fold in the tail domain of Drosophila melanogaster lamin Dm0, which binds chromatin in vitro via the histone H2A/H2B dimer. This region contains an evolutionarily conserved nuclear localization signal (NLS) KRKR, and a sequence composed of the amino acids TRAT. Here we show that binding of lamin Dm0 to chromatin requires both NLS and TRAT sequences. Substituting either of the threonine residues in the TRAT sequence with negatively charged residues decreases the binding of lamin Dm0 to chromatin, indicating that this binding could be regulated by phosphorylation. Both lamin Dm0 and C. elegans Ce-lamin bind directly to histone H2A in vitro and this binding requires the NLS. The amino and carboxyl tail domains of histone H2A are each essential, but not sufficient, for binding to lamin Dm0; only a polypeptide containing both histone H2A tail domains binds efficiently to lamin Dm0. Taken together, these results suggest that specific residues in lamin Dm0 and histone H2A mediate the attachment of the nuclear lamina to chromosomes in vivo, which could have implications on the understanding of laminopathic diseases.
Collapse
Affiliation(s)
- Anna Mattout
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904 Israel
| | | | | | | | | |
Collapse
|
53
|
Hübner S, Eam JE, Wagstaff KM, Jans DA. Quantitative analysis of localization and nuclear aggregate formation induced by GFP-lamin A mutant proteins in living HeLa cells. J Cell Biochem 2006; 98:810-26. [PMID: 16440304 DOI: 10.1002/jcb.20791] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Although A-type lamins are ubiquitously expressed, their role in the tissue-specificity of human laminopathies remains enigmatic. In this study, we generate a series of transfection constructs encoding missense lamin A mutant proteins fused to green fluorescent protein and investigate their subnuclear localization using quantitative live cell imaging. The mutant constructs used included the laminopathy-inducing lamin A rod domain mutants N195K, E358K, M371K, R386K, the tail domain mutants G465D, R482L, and R527P, and the Hutchinson-Gilford progeria syndrome-causing deletion mutant, progerin (LaA delta50). All mutant derivatives induced nuclear aggregates, except for progerin, which caused a more lobulated phenotype of the nucleus. Quantitative analysis revealed that the frequency of nuclear aggregate formation was significantly higher (two to four times) for the mutants compared to the wild type, although the level of lamin fusion proteins within nuclear aggregates was not. The distribution of endogenous A-type lamins was altered by overexpression of the lamin A mutants, coexpression experiments revealing that aberrant localization of the N195K and R386K mutants had no effect on the subnuclear distribution of histones H2A or H2B, or on nuclear accumulation of H2A overexpressed as a DsRed2 fusion protein. The GFP-lamin fusion protein-expressing constructs will have important applications in the future, enabling live cell imaging of nuclear processes involving lamins and how this may relate to the pathogenesis of laminopathies.
Collapse
Affiliation(s)
- S Hübner
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, PO Box 13D, Monash University, Clayton, Victoria 3800, Australia.
| | | | | | | |
Collapse
|
54
|
Broers JLV, Ramaekers FCS, Bonne G, Yaou RB, Hutchison CJ. Nuclear Lamins: Laminopathies and Their Role in Premature Ageing. Physiol Rev 2006; 86:967-1008. [PMID: 16816143 DOI: 10.1152/physrev.00047.2005] [Citation(s) in RCA: 441] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
It has been demonstrated that nuclear lamins are important proteins in maintaining cellular as well as nuclear integrity, and in maintaining chromatin organization in the nucleus. Moreover, there is growing evidence that lamins play a prominent role in transcriptional control. The family of laminopathies is a fast-growing group of diseases caused by abnormalities in the structure or processing of the lamin A/C ( LMNA) gene. Mutations or incorrect processing cause more than a dozen different inherited diseases, ranging from striated muscular diseases, via fat- and peripheral nerve cell diseases, to progeria. This broad spectrum of diseases can only be explained if the responsible A-type lamin proteins perform multiple functions in normal cells. This review gives an overview of current knowledge on lamin structure and function and all known diseases associated with LMNA abnormalities. Based on the knowledge of the different functions of A-type lamins and associated proteins, explanations for the observed phenotypes are postulated. It is concluded that lamins seem to be key players in, among others, controlling the process of cellular ageing, since disturbance in lamin protein structure gives rise to several forms of premature ageing.
Collapse
Affiliation(s)
- J L V Broers
- Department of Molecular Cell Biology, University of Maastricht, Research Institutes CARIM, GROW, and EURON, The Netherlands
| | | | | | | | | |
Collapse
|
55
|
Bao X, Zhang W, Krencik R, Deng H, Wang Y, Girton J, Johansen J, Johansen KM. The JIL-1 kinase interacts with lamin Dm0 and regulates nuclear lamina morphology of Drosophila nurse cells. J Cell Sci 2005; 118:5079-87. [PMID: 16254246 DOI: 10.1242/jcs.02611] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have used a yeast two-hybrid screen to identify lamin Dm0 as an interaction partner for the nuclear JIL-1 kinase. This molecular interaction was confirmed by GST-fusion protein pull-down assays and by co-immunoprecipitation experiments. Using deletion construct analysis we show that a predicted globular domain of the basic region of the COOH-terminal domain of JIL-1 was sufficient for mediating the molecular interactions with lamin Dm0. A reciprocal analysis with truncated lamin Dm0 constructs showed that the interaction with JIL-1 required sequences in the tail domain of lamin Dm0 that include the Ig-like fold. Further support for a molecular interaction between JIL-1 and lamin Dm0 in vivo was provided by genetic interaction assays. We show that nuclear positioning and lamina morphology were abnormal in JIL-1 mutant egg chambers. The most common phenotypes observed were abnormal nurse cell nuclear lamina protrusions through the ring canals near the oocyte, as well as dispersed and mislocalized lamin throughout the egg chamber. These phenotypes were completely rescued by a full-length JIL-1 transgenic construct. Thus, our results suggest that the JIL-1 kinase is required to maintain nuclear morphology and integrity of nurse cells during oogenesis and that this function may be linked to molecular interactions with lamin Dm0.
Collapse
Affiliation(s)
- Xiaomin Bao
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | | | | | | | | | | | | | | |
Collapse
|
56
|
Prather RS, Kühholzer B, Lai L, Park KW. Changes in the structure of nuclei after transfer to oocytes. ACTA ACUST UNITED AC 2005; 2:117-22. [PMID: 16218847 DOI: 10.1089/152045500750039815] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Nuclear transfer and the potential for cloning animals have refocused attention on the oocyte. This focus is not limited to the use of the oocyte as a recipient in nuclear transfer procedures, but more broadly in terms of what factors are present in the oocyte that are responsible for establishing the developmental pattern of RNA synthesis and subsequent protein production. Deviations in the pattern of RNA synthesis can result in abortions, as well as abnormalities at birth. This paper will focus on the changes to nuclear structure that result from transfer to the cytoplasm of an oocyte, as well as some of the changes in the patterns of RNA synthesis that have been described.
Collapse
Affiliation(s)
- R S Prather
- University of Missouri-Columbia, Columbia, MO 65211, USA.
| | | | | | | |
Collapse
|
57
|
Krohne G, Benavente R, Scheer U, Dabauvalle MC. The nuclear lamina in Heidelberg and Würzburg: a personal view. Eur J Cell Biol 2005; 84:163-79. [PMID: 15819398 DOI: 10.1016/j.ejcb.2004.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Georg Krohne
- Division of Electron Microscopy, Biocenter of the University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | | | | | | |
Collapse
|
58
|
Schulze SR, Curio-Penny B, Li Y, Imani RA, Rydberg L, Geyer PK, Wallrath LL. Molecular genetic analysis of the nested Drosophila melanogaster lamin C gene. Genetics 2005; 171:185-96. [PMID: 15965247 PMCID: PMC1456510 DOI: 10.1534/genetics.105.043208] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lamins are intermediate filaments that line the inner surface of the nuclear envelope, providing structural support and making contacts with chromatin. There are two types of lamins, A- and B-types, which differ in structure and expression. Drosophila possesses both lamin types, encoded by the LamC (A-type) and lamin Dm0 (B-type) genes. LamC is nested within an intron of the essential gene ttv. We demonstrate that null mutations in LamC are lethal, and expression of a wild-type LamC transgene rescues lethality of LamC but not ttv mutants. Mutations in the human A-type lamin gene lead to diseases called laminopathies. To determine if Drosophila might serve as a useful model to study lamin biology and disease mechanisms, we generated transgenic flies expressing mutant LamC proteins modeled after human disease-causing lamins. These transgenic animals display a nuclear lamin aggregation phenotype remarkably similar to that observed when human mutant A-type lamins are expressed in mammalian cells. LamC aggregates also cause disorganization of lamin Dm0, indicating interdependence of both lamin types for proper lamina assembly. Taken together, these data provide the first detailed genetic analysis of the LamC gene and support using Drosophila as a model to study the role of lamins in disease.
Collapse
Affiliation(s)
- Sandra R Schulze
- Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | | | | | | | | |
Collapse
|
59
|
Tunnah D, Sewry CA, Vaux D, Schirmer EC, Morris GE. The apparent absence of lamin B1 and emerin in many tissue nuclei is due to epitope masking. J Mol Histol 2005; 36:337-44. [PMID: 16283426 DOI: 10.1007/s10735-005-9004-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Accepted: 07/13/2005] [Indexed: 01/18/2023]
Abstract
Immunolocalization studies have concluded that the nuclear membrane protein, emerin, is absent from many cell types and that lamin B1 is absent from adult heart and skeletal muscle. We now show that epitope masking in the nucleus is often responsible for failure to detect emerin and lamins in human, rat and pig tissues. Human heart cardiomyocyte nuclei were negative for lamin B1 using a commercial mAb, but were positive using two other lamin B1 antibodies, mAb8D1 and pAbB1-cbs. Rat hippocampal neuronal nuclei were immunostained by mAb8D1, but not pAbB1-cbs, while the commercial antibody stained only a subset. These data suggest that different regions of the lamin B1 molecule are masked in different tissues. Similarly, pig spleen had fewer emerin-positive nuclei than lung (5% vs. 32%), although their emerin content was similar by Western blotting. As mAbs against six epitopes gave the same result, the whole emerin molecule is either masked or redistributed in a subset of cells. Our findings argue that immunostaining evidence can be misleading for expression of nuclear envelope proteins. Problems with lamin B1 immunostaining can be avoided by using mAb8D1, but use of antibodies recognizing different epitopes may reveal cell-specific protein interactions in the nucleus.
Collapse
Affiliation(s)
- Darran Tunnah
- Centre for Inherited Neuromuscular Disease, LMARC Building, Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, SY10 7AG, UK
| | | | | | | | | |
Collapse
|
60
|
Affiliation(s)
- Alexandra Fridkin
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | | | | |
Collapse
|
61
|
Worman HJ, Courvalin JC. Nuclear envelope, nuclear lamina, and inherited disease. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 246:231-79. [PMID: 16164970 DOI: 10.1016/s0074-7696(05)46006-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The nuclear envelope is composed of the nuclear membranes, nuclear lamina, and nuclear pore complexes. In recent years, mutations in nuclear-envelope proteins have been shown to cause a surprisingly wide array of inherited diseases. While the mutant proteins are generally expressed in most or all differentiated somatic cells, many mutations cause fairly tissue-specific disorders. Perhaps the most dramatic case is that of mutations in A-type lamins, intermediate filament proteins associated with the inner nuclear membrane. Different mutations in the same lamin proteins have been shown to cause striated muscle diseases, partial lipodystrophy syndromes, a peripheral neuropathy, and disorders with features of severe premature aging. In this review, we summarize fundamental aspects of nuclear envelope structure and function, the inherited diseases caused by mutations in lamins and other nuclear envelope proteins, and possible pathogenic mechanisms.
Collapse
Affiliation(s)
- Howard J Worman
- Department of Medicine and Department of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | | |
Collapse
|
62
|
Lin F, Morrison JM, Wu W, Worman HJ. MAN1, an integral protein of the inner nuclear membrane, binds Smad2 and Smad3 and antagonizes transforming growth factor-beta signaling. Hum Mol Genet 2004; 14:437-45. [PMID: 15601644 DOI: 10.1093/hmg/ddi040] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
MAN1 (also known as LEMD3) is an integral protein of the inner nuclear membrane. Recently, mutations in MAN1 have been shown to result in osteopoikilosis, Buschke-Ollendorff syndrome and melorheostosis. We show that the nucleoplasmic, C-terminal domain of human MAN1 binds to Smad2 and Smad3 and antagonizes signaling by transforming growth factor-beta (TGF-beta). In a yeast two-hybrid screen using the C-terminal domain of MAN1 as bait, eight positive clones were obtained that encoded Smad3. In direct two-hybrid assays, this portion of MAN1 bound to Smad2 and Smad3. In glutathione-S-transferase precipitation assays, the C-terminal domain of MAN1 bound to Smad2 and Smad3 under stringent conditions. Antibodies against MAN1 were able to co-immunoprecipiate Smad2 from cells, demonstrating that they reside in the same complex in vivo. TGF-beta treatment stimulated transcription from a reporter gene in control cells, but reporter gene stimulation was significantly inhibited in cells overexpressing MAN1 or its C-terminal domain but not its N-terminal domain. TGF-beta-induced cell proliferation arrest was also inhibited in stable cell lines overexpressing MAN1. These results show that the nuclear envelope regulates a signal transduction pathway and have implications for how mutations in nuclear envelope proteins cause different human diseases.
Collapse
Affiliation(s)
- Feng Lin
- Department of Medicine and Department of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | | | | | | |
Collapse
|
63
|
Dechat T, Gajewski A, Korbei B, Gerlich D, Daigle N, Haraguchi T, Furukawa K, Ellenberg J, Foisner R. LAP2α and BAF transiently localize to telomeres and specific regions on chromatin during nuclear assembly. J Cell Sci 2004; 117:6117-28. [PMID: 15546916 DOI: 10.1242/jcs.01529] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Lamina-associated polypeptide (LAP) 2α is a LEM (lamina-associated polypeptide emerin MAN1) family protein associated with nucleoplasmic A-type lamins and chromatin. Using live cell imaging and fluorescence microscopy we demonstrate that LAP2α was mostly cytoplasmic in metaphase and associated with telomeres in anaphase. Telomeric LAP2α clusters grew in size, formed `core' structures on chromatin adjacent to the spindle in telophase, and translocated to the nucleoplasm in G1 phase. A subfraction of lamin C and emerin followed LAP2α to the core region early on, whereas LAP2β, lamin B receptor and lamin B initially bound to more peripheral regions of chromatin, before they spread to core structures with different kinetics. Furthermore, the DNA-crosslinking protein barrier-to-autointegration factor (BAF) bound to LAP2α in vitro and in mitotic extracts, and subfractions of BAF relocalized to core structures with LAP2α. We propose that LAP2α and a subfraction of BAF form defined complexes in chromatin core regions and may be involved in chromatin reorganization during early stages of nuclear assembly.
Collapse
Affiliation(s)
- Thomas Dechat
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria
| | | | | | | | | | | | | | | | | |
Collapse
|
64
|
Abstract
Eukaryotic genomes are distributed on linear chromosomes that are grouped together in the nucleus, an organelle separated from the cytoplasm by a characteristic double membrane studded with large proteinaceous pores. The chromatin within chromosomes has an as yet poorly characterized higher-order structure, but in addition to this, chromosomes and specific subchromosomal domains are nonrandomly positioned in nuclei. This review examines functional implications of the long-range organization of the genome in interphase nuclei. A rigorous test of the physiological importance of nuclear architecture is achieved by introducing mutations that compromise both structure and function. Focussing on such genetic approaches, we address general concepts of interphase nuclear order, the role of the nuclear envelope (NE) and lamins, and finally the importance of spatial organization for DNA replication and heritable gene expression.
Collapse
Affiliation(s)
- Angela Taddei
- University of Geneva, Department of Molecular Biology, CH-1211 Geneva 4, Switzerland
| | | | | | | |
Collapse
|
65
|
Gajewski A, Csaszar E, Foisner R. A Phosphorylation Cluster in the Chromatin-binding Region Regulates Chromosome Association of LAP2α. J Biol Chem 2004; 279:35813-21. [PMID: 15208326 DOI: 10.1074/jbc.m402546200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
LAP2alpha is a LEM family protein associated with nucleoplasmic A-type lamins and chromatin in interphase. Like lamins and other lamina proteins LAP2alpha is cytoplasmic in metaphase, but it associates with chromosomes prior to nuclear envelope formation in late anaphase to telophase. In vitro phosphorylation analysis and mass spectrometry identified a cluster of at least three mitotic cyclin-dependent kinase 1 phosphorylation sites in the C-terminal chromatin-binding region of LAP2alpha as well as four additional potential sites in the cluster, some of which were targeted alternatively in LAP2alpha mutated at the major sites. LAP2alpha mutants containing serine --> alanine mutations at all seven sites revealed a clear phenotype. Mutated LAP2alpha remained associated with chromosomes throughout mitosis, but the dissociation of lamins into the cytoplasm and nuclear envelope disassembly were not affected. These data demonstrate the in vivo significance of mitotic phosphorylation for the dynamic behavior of LAP2alpha in the cell cycle and show that, unlike the interaction with lamins, the chromatin association of LAP2alpha is regulated by multiple mitosis-specific phosphorylation at sites clustered within a defined region in the C terminus of the protein.
Collapse
Affiliation(s)
- Andreas Gajewski
- Department of Medical Biochemistry, Medical University of Vienna, Austria
| | | | | |
Collapse
|
66
|
Gruenbaum Y, Goldman RD, Meyuhas R, Mills E, Margalit A, Fridkin A, Dayani Y, Prokocimer M, Enosh A. The nuclear lamina and its functions in the nucleus. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 226:1-62. [PMID: 12921235 DOI: 10.1016/s0074-7696(03)01001-5] [Citation(s) in RCA: 173] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The nuclear lamina is a structure near the inner nuclear membrane and the peripheral chromatin. It is composed of lamins, which are also present in the nuclear interior, and lamin-associated proteins. The increasing number of proteins that interact with lamins and the compound interactions between these proteins and chromatin-associated proteins make the nuclear lamina a highly complex but also a very exciting structure. The nuclear lamina is an essential component of metazoan cells. It is involved in most nuclear activities including DNA replication, RNA transcription, nuclear and chromatin organization, cell cycle regulation, cell development and differentiation, nuclear migration, and apoptosis. Specific mutations in nuclear lamina genes cause a wide range of heritable human diseases. These diseases include Emery-Dreifuss muscular dystrophy, limb girdle muscular dystrophy, dilated cardiomyopathy (DCM) with conduction system disease, familial partial lipodystrophy (FPLD), autosomal recessive axonal neuropathy (Charcot-Marie-Tooth disorder type 2, CMT2), mandibuloacral dysplasia (MAD), Hutchison Gilford Progeria syndrome (HGS), Greenberg Skeletal Dysplasia, and Pelger-Huet anomaly (PHA). Genetic analyses in Caenorhabditis elegans, Drosophila, and mice show new insights into the functions of the nuclear lamina, and recent structural analyses have begun to unravel the molecular structure and assembly of lamins and their associated proteins.
Collapse
Affiliation(s)
- Yosef Gruenbaum
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | | | | | | | | | | | | | | | | |
Collapse
|
67
|
Maraldi NM, Lattanzi G, Squarzoni S, Sabatelli P, Marmiroli S, Ognibene A, Manzoli FA. At the nucleus of the problem: nuclear proteins and disease. ADVANCES IN ENZYME REGULATION 2004; 43:411-43. [PMID: 12791400 DOI: 10.1016/s0065-2571(02)00042-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
68
|
Abstract
Development requires a precise program of gene expression to be carried out. Much work has focussed on the regulatory networks that control gene expression, for example in response to external cues. However, it is important to recognize that these regulatory events take place within the physical context of the nucleus, and that the physical position of a gene within the nuclear volume can have strong influences on its regulation and interactions. The first part of this review will summarize what is currently known about nuclear architecture, that is, the large-scale three-dimensional arrangement of chromosome loci within the nucleus. The remainder of the review will examine developmental processes from the point of view of the nucleus.
Collapse
Affiliation(s)
- Wallace F Marshall
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA.
| |
Collapse
|
69
|
Harris HL, Braig HR. Sperm chromatin remodelling and Wolbachia-induced cytoplasmic incompatibility in Drosophila. Biochem Cell Biol 2003; 81:229-40. [PMID: 12897857 DOI: 10.1139/o03-053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Wolbachia pipientis is an obligate bacterial endosymbiont, which has successfully invaded approximately 20% of all insect species by manipulating their normal developmental patterns. Wolbachia-induced phenotypes include parthenogenesis, male killing, and, most notably, cytoplasmic incompatibility. In the future these phenotypes might be useful in controlling or modifying insect populations but this will depend on our understanding of the basic molecular processes underlying insect fertilization and development. Wolbachia-infected Drosophila simulans express high levels of cytoplasmic incompatibility in which the sperm nucleus is modified and does not form a normal male pronucleus when fertilizing eggs from uninfected females. The sperm modification is somehow rescued in eggs infected with the same strain of Wolbachia. Thus, D. simulans has become an excellent model organism for investigating the manner in which endosymbionts can alter reproductive programs in insect hosts. This paper reviews the current knowledge of Drosophila early development and particularly sperm function. Developmental mutations in Drosophila that are known to affect sperm function will also be discussed.incompatibility.
Collapse
Affiliation(s)
- Harriet L Harris
- School of Biological Sciences, University of Wales, Bangor, Gwyneed, United Kingdom.
| | | |
Collapse
|
70
|
Abstract
Several neuromuscular diseases are caused by mutations in emerin and A-type lamins, proteins of the nuclear envelope. Emery-Dreifuss muscular dystrophy is caused by mutations in emerin (X-linked) or A-type lamins (autosomal dominant). Mutations in A-type lamins also cause limb-girdle muscular dystrophy type 1B, dilated cardiomyopathy with conduction defect, and Charcot-Marie-Tooth disorder type 2B1. They also cause partial lipodystrophy syndromes. The functions of emerin and A-type lamins and the mechanisms of how mutations in these proteins cause tissue-specific diseases are not well understood. The mutated proteins may cause structural damage to cells but may also affect processes such as gene regulation. This review gives an overview of this topic and describes recent advances in identification of disease-causing mutations, studies of cells and tissues from subjects with these diseases, and animal and cell culture models.
Collapse
Affiliation(s)
- Cecilia Ostlund
- Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, Tenth Floor, New York, New York 10032, USA
| | | |
Collapse
|
71
|
Zalenskaya IA, Zalensky AO. Telomeres in mammalian male germline cells. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 218:37-67. [PMID: 12199519 DOI: 10.1016/s0074-7696(02)18011-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Telomeres are terminal chromosomal domains that protect chromosome ends from degradation and fusion and promote complete replication of DNA. Telomeres are involved in the regulation of cellular replicative lifespan and tumorigenesis. These important functions of the telomeres have evoked high interest: numerous studies have resulted in a detailed description of telomere composition and structure in somatic cells. Much less is known about telomeres in germline cells. Emerging novel features and unique behavior of telomeres in the process of gamete differentiation suggest that they may have additional germline-specific function(s). This review describes recent studies revealing changes in the telomere organization in the course of differentiation from the germline stem cells to mature sperm in mammals. Similarities and differences between somatic and spermatogenic cells in telomere nuclear localization, protein composition, DNA length, telomerase activity, and chromatin structure are discussed. The exceptional features of the germline telomeres may be important for regulation of telomerase activity during spermatogenesis, homologous chromosome pairing during recombination, as well as for male pronucleus development and ordered chromosome withdrawal post-fertilization.
Collapse
Affiliation(s)
- Irina A Zalenskaya
- Department of Biological Chemistry, School of Medicine, University of California, Davis 95616, USA
| | | |
Collapse
|
72
|
Benvenuto G, Formiggini F, Laflamme P, Malakhov M, Bowler C. The photomorphogenesis regulator DET1 binds the amino-terminal tail of histone H2B in a nucleosome context. Curr Biol 2002; 12:1529-34. [PMID: 12225670 DOI: 10.1016/s0960-9822(02)01105-3] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Light provides a major source of information from the environment during plant growth and development. Recent results suggest that the key events controlling light-regulated gene expression in plants are translocation of the phytochrome photoreceptors into the nucleus, followed by their binding to transcription factors such as PIF3. Coupled with this, the degradation of positively acting intermediates such as the transcription factor HY5 by COP1 and the COP9 signalosome appears to be an important process whereby photomorphogenesis is repressed in darkness (e.g., ). Genetic analyses in Arabidopsis and tomato have revealed that the nuclear protein DET1 also plays a key role in the repression of photomorphogenesis. However, the function of this protein has remained a mystery. In a series of in vitro experiments, we provide persuasive evidence that DET1 binds to nonacetylated amino-terminal tails of the core histone H2B in the context of the nucleosome. Furthermore, we have utilized FRET (fluorescence resonance energy transfer) imaging with GFP variants to demonstrate this interaction within the nucleus of living plant cells. Given the dramatic photomorphogenic phenotypes of det1 mutants, we propose that chromatin remodeling plays a heretofore unsuspected role in regulating gene expression during photomorphogenesis.
Collapse
Affiliation(s)
- Giovanna Benvenuto
- Laboratory of Molecular Plant Biology, Stazione Zoologica Anton Dohrn, Villa Comunale, I-80121 Naples, Italy
| | | | | | | | | |
Collapse
|
73
|
Abstract
Chromosomes occupy distinct territories in the interphase cell nucleus. These chromosome territories are non-randomly arranged within the nuclear space. We are only just uncovering how chromosome territories are organized, what determines their position and how their spatial organization affects the expression of genes and genomes. Here, we discuss emerging models of non-random nuclear chromosome organization and consider the functional implications of chromosome positioning for gene expression and genome stability.
Collapse
Affiliation(s)
- Luis Parada
- National Cancer Inst., NIH, 20892, Bethesda, MD, USA
| | | |
Collapse
|
74
|
Dhe-Paganon S, Werner ED, Chi YI, Shoelson SE. Structure of the globular tail of nuclear lamin. J Biol Chem 2002; 277:17381-4. [PMID: 11901143 DOI: 10.1074/jbc.c200038200] [Citation(s) in RCA: 198] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nuclear lamins form a two-dimensional matrix that provides integrity to the cell nucleus and participates in nuclear activities. Mutations in the region of human LMNA encoding the carboxyl-terminal tail Lamin A/C are associated with forms of muscular dystrophy and familial partial lipodystrophy (FPLD). To help discriminate tissue-specific phenotypes, we have solved at 1.4-A resolution the three-dimensional crystal structure of the lamin A/C globular tail. The domain adopts a novel, all beta immunoglobulin-like fold. FPLD-associated mutations cluster within a small surface, whereas muscular dystrophy-associated mutations are distributed throughout the protein core and on its surface. These findings distinguish myopathy- and lipodystrophy-associated mutations and provide a structural framework for further testing hypotheses concerning lamin function.
Collapse
Affiliation(s)
- Sirano Dhe-Paganon
- Joslin Diabetes Center & Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA
| | | | | | | |
Collapse
|
75
|
Abstract
Fluorescence in situ hybridization combined with three-dimensional microscopy has shown that chromosomes are not randomly strewn throughout the nucleus but are in fact fairly well organized, with different loci reproducibly found in different regions of the nucleus. At the same time, increasingly sophisticated methods to track and analyze the movements of specific chromosomal loci in vivo using four-dimensional microscopy have revealed that chromatin undergoes extensive Brownian motion. However, the diffusion of interphase chromatin is constrained, implying that chromosomes are physically anchored within the nucleus. This constraint on diffusion is the result of interactions between chromatin and structural elements within the nucleus, such as nuclear pores or the nuclear lamina. The combination of defined positioning with constrained diffusion has a strong impact on interactions between chromosomal loci, and appears to explain the tendency of certain chromosome rearrangements to occur during the development of cancer.
Collapse
Affiliation(s)
- Wallace F Marshall
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.
| |
Collapse
|
76
|
Yu J, Wolfner MF. The Drosophila nuclear lamina protein YA binds to DNA and histone H2B with four domains. Mol Biol Cell 2002; 13:558-69. [PMID: 11854412 PMCID: PMC65649 DOI: 10.1091/mbc.01-07-0336] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Dramatic changes occur in nuclear organization and function during the critical developmental transition from meiosis to mitosis. The Drosophila nuclear lamina protein YA binds to chromatin and is uniquely required for this transition. In this study, we dissected YA's binding to chromatin. We found that YA can bind to chromatin directly and specifically. It binds to DNA but not RNA, with a preference for double-stranded DNA (linear or supercoiled) over single-stranded DNA. It also binds to histone H2B. YA's binding to DNA and histone H2B is mediated by four domains distributed along the length of the YA molecule. A model for YA function at the end of Drosophila female meiosis is proposed.
Collapse
Affiliation(s)
- Jing Yu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853-2703, USA
| | | |
Collapse
|
77
|
Vigouroux C, Auclair M, Dubosclard E, Pouchelet M, Capeau J, Courvalin JC, Buendia B. Nuclear envelope disorganization in fibroblasts from lipodystrophic patients with heterozygous R482Q/W mutations in the lamin A/C gene. J Cell Sci 2001; 114:4459-68. [PMID: 11792811 DOI: 10.1242/jcs.114.24.4459] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dunnigan-type familial partial lipodystrophy (FPLD), characterized by an abnormal body fat redistribution with insulin resistance, is caused by missense heterozygous mutations in A-type lamins (lamins A and C). A- and B-type lamins are ubiquitous intermediate filament proteins that polymerize at the inner face of the nuclear envelope. We have analyzed primary cultures of skin fibroblasts from three patients harboring R482Q or R482W mutations. These cells were euploid and able to cycle and divide. A subpopulation of these cells had abnormal blebbing nuclei with A-type lamins forming a peripheral meshwork, which was frequently disorganized. Inner nuclear membrane protein emerin, an A-type lamin-binding protein, strictly colocalized with this abnormal meshwork. Cells from lipodystrophic patients often had other nuclear envelope defects, mainly consisting of nuclear envelope herniations that were deficient in B-type lamins, nuclear pore complexes, lamina-associated protein 2 beta, and chromatin. The mechanical properties of nuclear envelopes were altered, as judged from the extensive deformations observed in nuclei from heat-shocked cells, and from the low stringency of extraction of their components. These structural nuclear alterations were caused by the lamins A/C mutations, as the same changes were introduced in human control fibroblasts by ectopic expression of R482W mutated lamin A.
Collapse
Affiliation(s)
- C Vigouroux
- INSERM U. 402, Faculté de Médecine Saint-Antoine, 75012 Paris, France
| | | | | | | | | | | | | |
Collapse
|
78
|
Tikoo K, Lau SS, Monks TJ. Histone H3 phosphorylation is coupled to poly-(ADP-ribosylation) during reactive oxygen species-induced cell death in renal proximal tubular epithelial cells. Mol Pharmacol 2001; 60:394-402. [PMID: 11455028 DOI: 10.1124/mol.60.2.394] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although the cellular response to chemical-induced stress is relatively well characterized, particularly the response to DNA damage, factors that govern the outcome of the stress response (cell survival or cell death) are less clearly defined. In this context, the mitogen-activated protein kinase (MAPK) family responds to a variety of physical and chemical stresses. The activation of MAPKs, especially the extracellular-regulated protein kinase subfamily, seems to play a causal role in death of renal proximal tubular epithelial cells (LLC-PK1) induced by reactive oxygen species (ROS). In this study, we show that extracellular signal receptor-activated kinase (ERK) activation may be coupled with LLC-PK1 cell death via changes in chromatin structure, which is mediated by increases in the phosphorylation of histone H3 (a post-translational modification required for both chromosome condensation and segregation during mitosis) and premature chromatin/chromosomal condensation, leading to cell death. In support of this view, 2,3,5-tris-(glutathione-S-yl)hydroquinone (TGHQ)-induced phosphorylation of histone H3 is accompanied by increases in chromatin condensation, as observed with the use of 4,6-diamidino-2-phenylindole-fluorescent staining, and by decreases in the sensitivity of chromatin to digestion by micrococcal nuclease. Changes in chromatin structure precede cell death. TGHQ-induced histone H3 phosphorylation and chromatin condensation are inhibited by PD098059, which selectively inhibits MAPK kinase, an upstream regulator of ERKs. Moreover, histone phosphorylation is modulated by poly(ADP-)ribosylation. Thus, the inhibition of poly(ADP-ribose)polymerase with 3-aminobenzamide prevents histone H3 phosphorylation and increases cell survival, suggesting that ADP-ribosylation and histone H3 phosphorylation are coupled in this model of ROS-induced DNA damage and cell death. The coupling of histone phosphorylation with ribosylation has not been previously demonstrated.
Collapse
Affiliation(s)
- K Tikoo
- Center for Molecular & Cellular Toxicology, Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, Texas, USA
| | | | | |
Collapse
|
79
|
Lopez-Soler RI, Moir RD, Spann TP, Stick R, Goldman RD. A role for nuclear lamins in nuclear envelope assembly. J Cell Biol 2001; 154:61-70. [PMID: 11448990 PMCID: PMC2196852 DOI: 10.1083/jcb.200101025] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2001] [Revised: 05/15/2001] [Accepted: 06/05/2001] [Indexed: 11/30/2022] Open
Abstract
The molecular interactions responsible for nuclear envelope assembly after mitosis are not well understood. In this study, we demonstrate that a peptide consisting of the COOH-terminal domain of Xenopus lamin B3 (LB3T) prevents nuclear envelope assembly in Xenopus interphase extracts. Specifically, LB3T inhibits chromatin decondensation and blocks the formation of both the nuclear lamina-pore complex and nuclear membranes. Under these conditions, some vesicles bind to the peripheral regions of the chromatin. These "nonfusogenic" vesicles lack lamin B3 (LB3) and do not bind LB3T; however, "fusogenic" vesicles containing LB3 can bind LB3T, which blocks their association with chromatin and, subsequently, nuclear membrane assembly. LB3T also binds to chromatin in the absence of interphase extract, but only in the presence of purified LB3. Additionally, we show that LB3T inhibits normal lamin polymerization in vitro. These findings suggest that lamin polymerization is required for both chromatin decondensation and the binding of nuclear membrane precursors during the early stages of normal nuclear envelope assembly.
Collapse
Affiliation(s)
- R I Lopez-Soler
- Department of Cell and Molecular Biology, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611, USA
| | | | | | | | | |
Collapse
|
80
|
Nesher G, Margalit R, Ashkenazi YJ. Anti-nuclear envelope antibodies: Clinical associations. Semin Arthritis Rheum 2001; 30:313-20. [PMID: 11303304 DOI: 10.1053/sarh.2001.20266] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Characterization of the clinical associations and clinical implications of antibodies reacting with antigens of the nuclear envelope. METHODS Description of an illustrative case and a MEDLINE search-assisted literature review of relevant cases. RESULTS With indirect immunofluorescence, autoantibodies directed against various antigens of the nuclear envelope stain the nucleus in a ring-like (rim) pattern. Autoantibodies against 5 antigenic components of the nuclear envelope have been described: anti-gp210, p62, lamina, lamina-associated polypeptides, and lamin B receptor. Antibodies to antigens of the nuclear pore complex, such as gp210 and p62, are highly specific (> 95%) for primary biliary cirrhosis and may aid in the serologic diagnosis of this condition, especially in cases in which antimitochondrial antibodies are not detectable. In contrast, antilamin antibodies are not disease-specific but seem to be associated with lupus anticoagulant or anticardiolipin antibodies, antiphospholipid syndrome, thrombocytopenia, autoimmune liver diseases, and arthralgia. High-titered antilamin antibodies help to define a subset of lupus patients with antiphospholipid antibodies who are at a lower risk of developing thrombotic events. In addition, preliminary data suggest that the presence of antilamin antibodies may be helpful in the diagnosis of chronic fatigue syndrome. CONCLUSIONS Each of the antibodies reacting with nuclear membrane antigens has its own spectrum of disease associations. RELEVANCE Determination of anti-nuclear envelope antibody pattern by indirect immunofluorescence, with subsequent determination of the specific antibody, carries important diagnostic and prognostic implications in various autoimmune conditions.
Collapse
Affiliation(s)
- G Nesher
- Department of Rheumatology Service, Hebrew University Medical School, Jerusalem, Israel.
| | | | | |
Collapse
|
81
|
Cohen M, Lee KK, Wilson KL, Gruenbaum Y. Transcriptional repression, apoptosis, human disease and the functional evolution of the nuclear lamina. Trends Biochem Sci 2001; 26:41-7. [PMID: 11165516 DOI: 10.1016/s0968-0004(00)01727-8] [Citation(s) in RCA: 210] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The number and complexity of genes encoding nuclear lamina proteins has increased during metazoan evolution. Emerging evidence reveals that transcriptional repressors such as the retinoblastoma protein, and apoptotic regulators such as CED-4, have functional and dynamic interactions with the lamina. The discovery that mutations in nuclear lamina proteins cause heritable tissue-specific diseases, including Emery-Dreifuss muscular dystrophy, is prompting a fresh look at the nuclear lamina to devise models that can account for its diverse functions and dynamics, and to understand its enigmatic structure.
Collapse
Affiliation(s)
- M Cohen
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | | | | | | |
Collapse
|
82
|
Gineitis AA, Zalenskaya IA, Yau PM, Bradbury EM, Zalensky AO. Human sperm telomere-binding complex involves histone H2B and secures telomere membrane attachment. J Cell Biol 2000; 151:1591-8. [PMID: 11134086 PMCID: PMC2150669 DOI: 10.1083/jcb.151.7.1591] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Telomeres are unique chromatin domains located at the ends of eukaryotic chromosomes. Telomere functions in somatic cells involve complexes between telomere proteins and TTAGGG DNA repeats. During the differentiation of germ-line cells, telomeres undergo significant reorganization most likely required for additional specific functions in meiosis and fertilization. A telomere-binding protein complex from human sperm (hSTBP) has been isolated by detergent treatment and was partially purified. hSTBP specifically binds double-stranded telomeric DNA and does not contain known somatic telomere proteins TRF1, TRF2, and Ku. Surprisingly, the essential component of this complex has been identified as a specific variant of histone H2B. Indirect immunofluorescence shows punctate localization of H2B in sperm nuclei, which in part coincides with telomeric DNA localization established by fluorescent in situ hybridization. Anti-H2B antibodies block interactions of hSTBP with telomere DNA, and spH2B forms specific complex with this DNA in vitro, indicating that this protein plays a role in telomere DNA recognition. We propose that hSTBP participates in the membrane attachment of telomeres that may be important for ordered chromosome withdrawal after fertilization.
Collapse
Affiliation(s)
- Arunas A. Gineitis
- Department of Biological Chemistry, School of Medicine, University of California at Davis, Davis, California 95616
- Institute of Biochemistry, Lithuanian Academy of Sciences, Vilnius, Lithuania 2001
| | - Irina A. Zalenskaya
- Department of Biological Chemistry, School of Medicine, University of California at Davis, Davis, California 95616
| | - Peter M. Yau
- Department of Biological Chemistry, School of Medicine, University of California at Davis, Davis, California 95616
| | - E. Morton Bradbury
- Department of Biological Chemistry, School of Medicine, University of California at Davis, Davis, California 95616
- Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Andrei O. Zalensky
- Department of Biological Chemistry, School of Medicine, University of California at Davis, Davis, California 95616
| |
Collapse
|
83
|
Martins SB, Eide T, Steen RL, Jahnsen T, Skålhegg B S, Collas P. HA95 is a protein of the chromatin and nuclear matrix regulating nuclear envelope dynamics. J Cell Sci 2000; 113 Pt 21:3703-13. [PMID: 11034899 DOI: 10.1242/jcs.113.21.3703] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report a role for HA95, a nuclear protein with high homology to the nuclear A-kinase anchoring protein AKAP95, in the regulation of nuclear envelope-chromatin interactions. Biochemical and photobleaching data indicate that HA95 is tightly associated with chromatin and the nuclear matrix/lamina network in interphase, and bound to chromatin at mitosis. HA95 resides in a complex together with lamin B receptor (LBR), lamina-associated polypeptide (LAP)2 and emerin, integral proteins of the inner nuclear membrane. Cross-linking experiments, however, illustrate a tight association of HA95 with LBR and LAP2 only. Intra-nuclear blocking of HA95 with anti-HA95 antibodies abolishes nuclear breakdown in a mitotic HeLa cell extract. The antibodies inhibit nuclear membrane breakdown and chromatin condensation - the latter independently of nuclear membranes. However, lamina disassembly is not affected, as judged by immunological analyses of A/C- and B-type lamins. In contrast, immunoblocking of HA95 bound to condensed chromosomes does not impair chromatin decondensation, nuclear membrane reassembly or lamina reformation. Our results argue for a role for HA95 in anchoring nuclear membranes and lamins to chromatin in interphase, and in releasing membranes from chromatin at mitosis. The data also suggest that HA95 is not involved in initial binding of membranes to chromatin upon nuclear reassembly. We propose that HA95 is a central platform at the chromatin/nuclear matrix interface implicated in regulating nuclear envelope-chromatin interactions during the cell cycle.
Collapse
Affiliation(s)
- S B Martins
- Institute of Medical Biochemistry, University of Oslo, PO Box 1112 Blindern, Norway
| | | | | | | | | | | |
Collapse
|
84
|
Liu J, Rolef Ben-Shahar T, Riemer D, Treinin M, Spann P, Weber K, Fire A, Gruenbaum Y. Essential roles for Caenorhabditis elegans lamin gene in nuclear organization, cell cycle progression, and spatial organization of nuclear pore complexes. Mol Biol Cell 2000; 11:3937-47. [PMID: 11071918 PMCID: PMC15048 DOI: 10.1091/mbc.11.11.3937] [Citation(s) in RCA: 319] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Caenorhabditis elegans has a single lamin gene, designated lmn-1 (previously termed CeLam-1). Antibodies raised against the lmn-1 product (Ce-lamin) detected a 64-kDa nuclear envelope protein. Ce-lamin was detected in the nuclear periphery of all cells except sperm and was found in the nuclear interior in embryonic cells and in a fraction of adult cells. Reductions in the amount of Ce-lamin protein produce embryonic lethality. Although the majority of affected embryos survive to produce several hundred nuclei, defects can be detected as early as the first nuclear divisions. Abnormalities include rapid changes in nuclear morphology during interphase, loss of chromosomes, unequal separation of chromosomes into daughter nuclei, abnormal condensation of chromatin, an increase in DNA content, and abnormal distribution of nuclear pore complexes (NPCs). Under conditions of incomplete RNA interference, a fraction of embryos escaped embryonic arrest and continue to develop through larval life. These animals exhibit additional phenotypes including sterility and defective segregation of chromosomes in germ cells. Our observations show that lmn-1 is an essential gene in C. elegans, and that the nuclear lamins are involved in chromatin organization, cell cycle progression, chromosome segregation, and correct spacing of NPCs.
Collapse
Affiliation(s)
- J Liu
- Department of Embryology, Carnegie Institution of Washington, Baltimore, Maryland 21210, USA
| | | | | | | | | | | | | | | |
Collapse
|
85
|
Dechat T, Korbei B, Vaughan OA, Vlcek S, Hutchison CJ, Foisner R. Lamina-associated polypeptide 2alpha binds intranuclear A-type lamins. J Cell Sci 2000; 113 Pt 19:3473-84. [PMID: 10984438 DOI: 10.1242/jcs.113.19.3473] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The nucleoskeletal protein lamina-associated polypeptide 2(α) (LAP2*) contains a large, unique C terminus and differs significantly from its alternatively spliced, mostly membrane-integrated isoforms, such as LAP2beta. Unlike lamin B-binding LAP2beta, LAP2alpha was found by confocal immunofluorescence microscopy to colocalize preferentially with A-type lamins in the newly formed nuclei assembled after mitosis. While only a subfraction of lamins A and C (lamin A/C) was associated with the predominantly nuclear LAP2alpha in telophase, the majority of lamin A/C colocalized with LAP2alpha in G(1)-phase nuclei. Furthermore, selective disruption of A-type lamin structures by overexpression of lamin mutants in HeLa cells caused a redistribution of LAP2alpha. Coimmunoprecipitation experiments revealed that a fraction of lamin A/C formed a stable, SDS-resistant complex with LAP2alpha in interphase cells and in postmetaphase cell extracts. Blot overlay binding studies revealed a direct binding of LAP2alpha to exclusively A-type lamins and located the interaction domains to the C-terminal 78 amino acids of LAP2alpha and to residues 319–566 in lamin A/C, which include the C terminus of the rod and the entire tail common to lamin A/C. These findings suggest that LAP2alpha and A-type lamins cooperate in the organization of internal nuclear structures.
Collapse
Affiliation(s)
- T Dechat
- Department of Biochemistry and Molecular Cell Biology, Vienna Biocenter, University of Vienna, A-1030 Vienna, Austria
| | | | | | | | | | | |
Collapse
|
86
|
Gruenbaum Y, Wilson KL, Harel A, Goldberg M, Cohen M. Review: nuclear lamins--structural proteins with fundamental functions. J Struct Biol 2000; 129:313-23. [PMID: 10806082 DOI: 10.1006/jsbi.2000.4216] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nuclear lamina is located between the inner nuclear membrane and the peripheral chromatin. It is composed of both peripheral and integral membrane proteins, including lamins and lamina-associated proteins. Lamins can interact with one another, with lamina-associated proteins, with nuclear scaffold proteins, and with chromatin. Likewise, most of the lamina-associated proteins are likely to interact directly with chromatin. The nuclear lamina is required for proper cell cycle regulation, chromatin organization, DNA replication, cell differentiation, and apoptosis. Mutations in proteins of the nuclear lamina can disrupt these activities and cause genetic diseases. The structure and assembly of the nuclear lamina proteins and their roles in chromatin organization and cell cycle regulation were recently reviewed. In this review, we discuss the roles of the nuclear lamina in DNA replication and apoptosis and analyze how mutations in nuclear lamina proteins might cause genetic diseases.
Collapse
Affiliation(s)
- Y Gruenbaum
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
| | | | | | | | | |
Collapse
|
87
|
Abstract
Lamins and other nuclear envelope proteins organize nuclear architecture through structural attachments that vary dynamically during the cell cycle and cell differentiation. Genetic studies have now shown that people with mutations in either lamins A/C or emerin, a nuclear membrane protein, develop Emery-Dreifuss muscular dystrophy. A mouse model for this rare disease has been created by knocking out the gene that encodes lamin A/C. This article discusses these and other recent results in the wider context of nuclear envelope function, as a framework for thinking about the possible ways in which defects in nuclear envelope proteins can lead to disease.
Collapse
Affiliation(s)
- K L Wilson
- Dept of Cell Biology and Anatomy, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
| |
Collapse
|