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Maharaj AV, Cottrell E, Thanasupawat T, Joustra SD, Triggs-Raine B, Fujimoto M, Kant SG, van der Kaay D, Clement-de Boers A, Brooks AS, Aguirre GA, Martín del Estal I, Castilla de Cortázar Larrea MI, Massoud A, van Duyvenvoorde HA, De Bruin C, Hwa V, Klonisch T, Hombach-Klonisch S, Storr HL. Characterization of HMGA2 variants expands the spectrum of Silver-Russell syndrome. JCI Insight 2024; 9:e169425. [PMID: 38516887 PMCID: PMC11063932 DOI: 10.1172/jci.insight.169425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 02/08/2024] [Indexed: 03/23/2024] Open
Abstract
Silver-Russell syndrome (SRS) is a heterogeneous disorder characterized by intrauterine and postnatal growth retardation. HMGA2 variants are a rare cause of SRS and its functional role in human linear growth is unclear. Patients with suspected SRS negative for 11p15LOM/mUPD7 underwent whole-exome and/or targeted-genome sequencing. Mutant HMGA2 protein expression and nuclear localization were assessed. Two Hmga2-knockin mouse models were generated. Five clinical SRS patients harbored HMGA2 variants with differing functional impacts: 2 stop-gain nonsense variants (c.49G>T, c.52C>T), c.166A>G missense variant, and 2 frameshift variants (c.144delC, c.145delA) leading to an identical, extended-length protein. Phenotypic features were highly variable. Nuclear localization was reduced/absent for all variants except c.166A>G. Homozygous knockin mice recapitulating the c.166A>G variant (Hmga2K56E) exhibited a growth-restricted phenotype. An Hmga2Ter76-knockin mouse model lacked detectable full-length Hmga2 protein, similarly to patient 3 and 5 variants. These mice were infertile, with a pygmy phenotype. We report a heterogeneous group of individuals with SRS harboring variants in HMGA2 and describe the first Hmga2 missense knockin mouse model (Hmga2K56E) to our knowledge causing a growth-restricted phenotype. In patients with clinical features of SRS but negative genetic screening, HMGA2 should be included in next-generation sequencing testing approaches.
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Affiliation(s)
- Avinaash V. Maharaj
- Centre for Endocrinology, William Harvey Research Institute, QMUL, London, United Kingdom
| | - Emily Cottrell
- Centre for Endocrinology, William Harvey Research Institute, QMUL, London, United Kingdom
| | - Thatchawan Thanasupawat
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Sjoerd D. Joustra
- Division of Paediatric Endocrinology, Department of Paediatrics, Willem-Alexander Children’s Hospital, Leiden University Medical Centre, Leiden, Netherlands
| | - Barbara Triggs-Raine
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Masanobu Fujimoto
- Cincinnati Center for Growth Disorders, Division of Endocrinology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, USA
| | - Sarina G. Kant
- Division of Paediatric Endocrinology, Department of Paediatrics, Willem-Alexander Children’s Hospital, Leiden University Medical Centre, Leiden, Netherlands
| | - Danielle van der Kaay
- Division of Paediatric Endocrinology, Department of Paediatrics, Erasmus University Medical Centre, Sophia Children’s Hospital, Rotterdam, Netherlands
| | - Agnes Clement-de Boers
- Department of Paediatrics, Juliana Children’s Hospital/Haga Teaching Hospital, The Hague, Netherlands
| | - Alice S. Brooks
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, Netherlands
| | | | | | | | - Ahmed Massoud
- Department of Paediatrics and Child Health, HCA Healthcare UK, London, United Kingdom
| | - Hermine A. van Duyvenvoorde
- Laboratory for Diagnostic Genome analysis (LDGA), Department of Clinical Genetics, Leiden University Medical Centre, Leiden, Netherlands
| | - Christiaan De Bruin
- Division of Paediatric Endocrinology, Department of Paediatrics, Willem-Alexander Children’s Hospital, Leiden University Medical Centre, Leiden, Netherlands
| | - Vivian Hwa
- Cincinnati Center for Growth Disorders, Division of Endocrinology, Cincinnati Children’s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, USA
| | - Thomas Klonisch
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pathology, and
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Sabine Hombach-Klonisch
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pathology, and
| | - Helen L. Storr
- Centre for Endocrinology, William Harvey Research Institute, QMUL, London, United Kingdom
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Norris V, Kayser C, Muskhelishvili G, Konto-Ghiorghi Y. The roles of nucleoid-associated proteins and topoisomerases in chromosome structure, strand segregation, and the generation of phenotypic heterogeneity in bacteria. FEMS Microbiol Rev 2023; 47:fuac049. [PMID: 36549664 DOI: 10.1093/femsre/fuac049] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 12/06/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022] Open
Abstract
How to adapt to a changing environment is a fundamental, recurrent problem confronting cells. One solution is for cells to organize their constituents into a limited number of spatially extended, functionally relevant, macromolecular assemblies or hyperstructures, and then to segregate these hyperstructures asymmetrically into daughter cells. This asymmetric segregation becomes a particularly powerful way of generating a coherent phenotypic diversity when the segregation of certain hyperstructures is with only one of the parental DNA strands and when this pattern of segregation continues over successive generations. Candidate hyperstructures for such asymmetric segregation in prokaryotes include those containing the nucleoid-associated proteins (NAPs) and the topoisomerases. Another solution to the problem of creating a coherent phenotypic diversity is by creating a growth-environment-dependent gradient of supercoiling generated along the replication origin-to-terminus axis of the bacterial chromosome. This gradient is modulated by transcription, NAPs, and topoisomerases. Here, we focus primarily on two topoisomerases, TopoIV and DNA gyrase in Escherichia coli, on three of its NAPs (H-NS, HU, and IHF), and on the single-stranded binding protein, SSB. We propose that the combination of supercoiling-gradient-dependent and strand-segregation-dependent topoisomerase activities result in significant differences in the supercoiling of daughter chromosomes, and hence in the phenotypes of daughter cells.
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Affiliation(s)
- Vic Norris
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Clara Kayser
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Georgi Muskhelishvili
- Agricultural University of Georgia, School of Natural Sciences, 0159 Tbilisi, Georgia
| | - Yoan Konto-Ghiorghi
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
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3
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Kasho K, Ozaki S, Katayama T. IHF and Fis as Escherichia coli Cell Cycle Regulators: Activation of the Replication Origin oriC and the Regulatory Cycle of the DnaA Initiator. Int J Mol Sci 2023; 24:11572. [PMID: 37511331 PMCID: PMC10380432 DOI: 10.3390/ijms241411572] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023] Open
Abstract
This review summarizes current knowledge about the mechanisms of timely binding and dissociation of two nucleoid proteins, IHF and Fis, which play fundamental roles in the initiation of chromosomal DNA replication in Escherichia coli. Replication is initiated from a unique replication origin called oriC and is tightly regulated so that it occurs only once per cell cycle. The timing of replication initiation at oriC is rigidly controlled by the timely binding of the initiator protein DnaA and IHF to oriC. The first part of this review presents up-to-date knowledge about the timely stabilization of oriC-IHF binding at oriC during replication initiation. Recent advances in our understanding of the genome-wide profile of cell cycle-coordinated IHF binding have revealed the oriC-specific stabilization of IHF binding by ATP-DnaA oligomers at oriC and by an initiation-specific IHF binding consensus sequence at oriC. The second part of this review summarizes the mechanism of the timely regulation of DnaA activity via the chromosomal loci DARS2 (DnaA-reactivating sequence 2) and datA. The timing of replication initiation at oriC is controlled predominantly by the phosphorylated form of the adenosine nucleotide bound to DnaA, i.e., ATP-DnaA, but not ADP-ADP, is competent for initiation. Before initiation, DARS2 increases the level of ATP-DnaA by stimulating the exchange of ADP for ATP on DnaA. This DARS2 function is activated by the site-specific and timely binding of both IHF and Fis within DARS2. After initiation, another chromosomal locus, datA, which inactivates ATP-DnaA by stimulating ATP hydrolysis, is activated by the timely binding of IHF. A recent study has shown that ATP-DnaA oligomers formed at DARS2-Fis binding sites competitively dissociate Fis via negative feedback, whereas IHF regulation at DARS2 and datA still remains to be investigated. This review summarizes the current knowledge about the specific role of IHF and Fis in the regulation of replication initiation and proposes a mechanism for the regulation of timely IHF binding and dissociation at DARS2 and datA.
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Affiliation(s)
- Kazutoshi Kasho
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Ribeiro J, Crossan GP. GCNA is a histone binding protein required for spermatogonial stem cell maintenance. Nucleic Acids Res 2023; 51:4791-4813. [PMID: 36919611 PMCID: PMC10250205 DOI: 10.1093/nar/gkad168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 02/01/2023] [Accepted: 02/28/2023] [Indexed: 03/16/2023] Open
Abstract
Recycling and de-novo deposition of histones during DNA replication is a critical challenge faced by eukaryotic cells and is coordinated by histone chaperones. Spermatogenesis is highly regulated sophisticated process necessitating not only histone modification but loading of testis specific histone variants. Here, we show that Germ Cell Nuclear Acidic protein (GCNA), a germ cell specific protein in adult mice, can bind histones and purified GCNA exhibits histone chaperone activity. GCNA associates with the DNA replication machinery and supports progression through S-phase in murine undifferentiated spermatogonia (USGs). Whilst GCNA is dispensable for embryonic germ cell development, it is required for the maintenance of the USG pool and for long-term production of sperm. Our work describes the role of a germ cell specific histone chaperone in USGs maintenance in mice. These findings provide a mechanistic basis for the male infertility observed in patients carrying GCNA mutations.
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Dorman CJ. Variable DNA topology is an epigenetic generator of physiological heterogeneity in bacterial populations. Mol Microbiol 2023; 119:19-28. [PMID: 36565252 PMCID: PMC10108321 DOI: 10.1111/mmi.15014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/25/2022] [Accepted: 12/06/2022] [Indexed: 12/25/2022]
Abstract
Transcription is a noisy and stochastic process that produces sibling-to-sibling variations in physiology across a population of genetically identical cells. This pattern of diversity reflects, in part, the burst-like nature of transcription. Transcription bursting has many causes and a failure to remove the supercoils that accumulate in DNA during transcription elongation is an important contributor. Positive supercoiling of the DNA ahead of the transcription elongation complex can result in RNA polymerase stalling if this DNA topological roadblock is not removed. The relaxation of these positive supercoils is performed by the ATP-dependent type II topoisomerases DNA gyrase and topoisomerase IV. Interference with the action of these topoisomerases involving, inter alia, topoisomerase poisons, fluctuations in the [ATP]/[ADP] ratio, and/or the intervention of nucleoid-associated proteins with GapR-like or YejK-like activities, may have consequences for the smooth operation of the transcriptional machinery. Antibiotic-tolerant (but not resistant) persister cells are among the phenotypic outliers that may emerge. However, interference with type II topoisomerase activity can have much broader consequences, making it an important epigenetic driver of physiological diversity in the bacterial population.
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Affiliation(s)
- Charles J Dorman
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
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Muskhelishvili G, Sobetzko P, Travers A. Spatiotemporal Coupling of DNA Supercoiling and Genomic Sequence Organization-A Timing Chain for the Bacterial Growth Cycle? Biomolecules 2022; 12:biom12060831. [PMID: 35740956 PMCID: PMC9221221 DOI: 10.3390/biom12060831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/08/2022] [Accepted: 06/08/2022] [Indexed: 01/25/2023] Open
Abstract
In this article we describe the bacterial growth cycle as a closed, self-reproducing, or autopoietic circuit, reestablishing the physiological state of stationary cells initially inoculated in the growth medium. In batch culture, this process of self-reproduction is associated with the gradual decline in available metabolic energy and corresponding change in the physiological state of the population as a function of "travelled distance" along the autopoietic path. We argue that this directional alteration of cell physiology is both reflected in and supported by sequential gene expression along the chromosomal OriC-Ter axis. We propose that during the E. coli growth cycle, the spatiotemporal order of gene expression is established by coupling the temporal gradient of supercoiling energy to the spatial gradient of DNA thermodynamic stability along the chromosomal OriC-Ter axis.
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Affiliation(s)
- Georgi Muskhelishvili
- School of Natural Sciences, Biology Program, Agricultural University of Georgia, 0159 Tbilisi, Georgia
- Correspondence:
| | - Patrick Sobetzko
- Synmikro, Loewe Center for Synthetic Microbiology, Philipps-Universität Marburg, 35043 Marburg, Germany;
| | - Andrew Travers
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK;
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Xu W, Yan Y, Artsimovitch I, Dunlap D, Finzi L. Positive supercoiling favors transcription elongation through lac repressor-mediated DNA loops. Nucleic Acids Res 2022; 50:2826-2835. [PMID: 35188572 PMCID: PMC8934669 DOI: 10.1093/nar/gkac093] [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: 10/07/2021] [Revised: 12/22/2021] [Accepted: 02/20/2022] [Indexed: 11/30/2022] Open
Abstract
Some proteins, like the lac repressor (LacI), mediate long-range loops that alter DNA topology and create torsional barriers. During transcription, RNA polymerase generates supercoiling that may facilitate passage through such barriers. We monitored E. coli RNA polymerase progress along templates in conditions that prevented, or favored, 400 bp LacI-mediated DNA looping. Tethered particle motion measurements revealed that RNA polymerase paused longer at unlooped LacI obstacles or those barring entry to a loop than those barring exit from the loop. Enhanced dissociation of a LacI roadblock by the positive supercoiling generated ahead of a transcribing RNA polymerase within a torsion-constrained DNA loop may be responsible for this reduction in pause time. In support of this idea, RNA polymerase transcribed 6-fold more slowly through looped DNA and paused at LacI obstacles for 66% less time on positively supercoiled compared to relaxed templates, especially under increased tension (torque). Positive supercoiling propagating ahead of polymerase facilitated elongation along topologically complex, protein-coated templates.
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Affiliation(s)
- Wenxuan Xu
- Physics Department, Emory University, Atlanta, GA, USA
| | - Yan Yan
- Physics Department, Emory University, Atlanta, GA, USA
| | | | - David Dunlap
- Physics Department, Emory University, Atlanta, GA, USA
| | - Laura Finzi
- Physics Department, Emory University, Atlanta, GA, USA
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8
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Huang Q, Duan B, Qu Z, Fan S, Xia B. The DNA Recognition Motif of GapR Has an Intrinsic DNA Binding Preference towards AT-rich DNA. MOLECULES (BASEL, SWITZERLAND) 2021; 26:molecules26195776. [PMID: 34641320 PMCID: PMC8510090 DOI: 10.3390/molecules26195776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 01/09/2023]
Abstract
The nucleoid-associated protein GapR found in Caulobacter crescentus is crucial for DNA replication, transcription, and cell division. Associated with overtwisted DNA in front of replication forks and the 3' end of highly-expressed genes, GapR can stimulate gyrase and topo IV to relax (+) supercoils, thus facilitating the movement of the replication and transcription machines. GapR forms a dimer-of-dimers structure in solution that can exist in either an open or a closed conformation. It initially binds DNA through the open conformation and then undergoes structural rearrangement to form a closed tetramer, with DNA wrapped in the central channel. Here, we show that the DNA binding domain of GapR (residues 1-72, GapRΔC17) exists as a dimer in solution and adopts the same fold as the two dimer units in the full-length tetrameric protein. It binds DNA at the minor groove and reads the spatial distribution of DNA phosphate groups through a lysine/arginine network, with a preference towards AT-rich overtwisted DNA. These findings indicate that the dimer unit of GapR has an intrinsic DNA binding preference. Thus, at the initial binding step, the open tetramer of GapR with two relatively independent dimer units can be more efficiently recruited to overtwisted regions.
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Affiliation(s)
- Qian Huang
- Beijing Nuclear Magnetic Resonance Center, School of Life Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; (Q.H.); (B.D.); (Z.Q.)
| | - Bo Duan
- Beijing Nuclear Magnetic Resonance Center, School of Life Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; (Q.H.); (B.D.); (Z.Q.)
| | - Zhi Qu
- Beijing Nuclear Magnetic Resonance Center, School of Life Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; (Q.H.); (B.D.); (Z.Q.)
| | - Shilong Fan
- The Technology Center for Protein Sciences, Tsinghua University, Beijing 100084, China
- Correspondence: (S.F.); (B.X.)
| | - Bin Xia
- Beijing Nuclear Magnetic Resonance Center, School of Life Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; (Q.H.); (B.D.); (Z.Q.)
- Correspondence: (S.F.); (B.X.)
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Shi Z, Wu D, Xu H, Yang J, Sun X. CSNK2A1-mediated phosphorylation of HMGA2 modulates cisplatin resistance in cervical cancer. FEBS Open Bio 2021. [PMID: 34115920 DOI: 10.1002/2211-5463.13228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 05/14/2021] [Accepted: 06/10/2021] [Indexed: 11/06/2022] Open
Abstract
The development of chemoresistance reduces the efficacy of anti-cancer drugs. Cervical cancer is still one of the most common cancer types in developing countries. The oncogenic protein high mobility group AT-hook 2 (HMGA2) is involved in the development and progression of tumors, although its role in chemoresistance of cervical cancer remains unclear. Here, we report that HMGA2 is highly expressed in cervical cancer and negatively correlated with cisplatin-induced cell death. We performed liquid chromatography-tandem mass spectrometry to demonstrate that HMGA2 has high potential to interact with casein kinase II A1 (CSNK2A1). Moreover, we observed that HMGA2 co-localizes with CSNK2A1 in the nucleus by immunofluorescence. Binding of HMGA2-CSNK2A1 was detected by immunoprecipitation assays. In addition, we identified that cisplatin induces an interaction between CSNK2A1 and HMGA2, thereby promoting the phosphorylation of HMGA2. CX-4945, a CSNK2A1 inhibitor, could inhibit the phosphorylation of HMGA2 and sensitize tumor cells to cisplatin. Our results reveal that CSNK2A1-dependent HMGA2 phosphorylation may partially underlie cisplatin-resistance in cervical cancer, suggesting that HMGA2 phosphorylation may have potential as a predicative biomarker and therapeutic target to improve chemotherapeutic efficacy.
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Affiliation(s)
- Zhan Shi
- Translational Medicine Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ding Wu
- Department of Urology, Jinling Hospital, Nanjing Medical University, Nanjing, China
| | - Hao Xu
- Department of Urology, Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Edong Healthcare Group, Huangshi, China
| | - Ju Yang
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University, Clinical Cancer Institute of Nanjing University, Nanjing, China
| | - Xiaoqing Sun
- Department of Urology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
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What Are the Potential Roles of Nuclear Perlecan and Other Heparan Sulphate Proteoglycans in the Normal and Malignant Phenotype. Int J Mol Sci 2021; 22:ijms22094415. [PMID: 33922532 PMCID: PMC8122901 DOI: 10.3390/ijms22094415] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 12/27/2022] Open
Abstract
The recent discovery of nuclear and perinuclear perlecan in annulus fibrosus and nucleus pulposus cells and its known matrix stabilizing properties in tissues introduces the possibility that perlecan may also have intracellular stabilizing or regulatory roles through interactions with nuclear envelope or cytoskeletal proteins or roles in nucleosomal-chromatin organization that may regulate transcriptional factors and modulate gene expression. The nucleus is a mechano-sensor organelle, and sophisticated dynamic mechanoresponsive cytoskeletal and nuclear envelope components support and protect the nucleus, allowing it to perceive and respond to mechano-stimulation. This review speculates on the potential roles of perlecan in the nucleus based on what is already known about nuclear heparan sulphate proteoglycans. Perlecan is frequently found in the nuclei of tumour cells; however, its specific role in these diseased tissues is largely unknown. The aim of this review is to highlight probable roles for this intriguing interactive regulatory proteoglycan in the nucleus of normal and malignant cell types.
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