scholarly journals Loss and gain of function experiments implicate TMEM18 as a mediator of the strong association between genetic variants at human Chromosome 2p25.3 and obesity

2017 ◽  
Author(s):  
Rachel Larder ◽  
M. F. Michelle Sim ◽  
Pawan Gulati ◽  
Robin Antrobus ◽  
Y.C. Loraine Tung ◽  
...  
Keyword(s):  
Food Intake ◽  
Human Chromosome ◽  
Nuclear Membrane ◽  
Genetic Variants ◽  
Molecular Mechanisms ◽  
Transmembrane Protein ◽  
Strong Association ◽  
Nuclear Pore ◽  
Chromosome 2 ◽  
The Impact

AbstractAn intergenic region of human Chromosome 2 (2p25.3) harbours genetic variants which are among those most strongly and reproducibly associated with obesity. The molecular mechanisms mediating these effects remain entirely unknown. The gene closest to these variants is TMEM18, encoding a transmembrane protein localised to the nuclear membrane. The expression of Tmem18 within the murine hypothalamic paraventricular nucleus was altered by changes in nutritional state, with no significant change seen in three other closest genes. Germline loss of Tmem18 in mice resulted in increased body weight, which was exacerbated by high fat diet and driven by increased food intake. Selective overexpression of Tmem18 in the PVN of wild-type mice reduced food intake and also increased energy expenditure. We confirmed the nuclear membrane localisation of TMEM18 but provide new evidence that it is has four, not three, transmembrane domains and that it physically interacts with key components of the nuclear pore complex. Our data support the hypothesis that TMEM18 itself, acting within the central nervous system, is a plausible mediator of the impact of adjacent genetic variation on human adiposity.

scholarly journals Obesity-associated gene TMEM18 has a role in the central control of appetite and body weight regulation

2017 ◽  
Vol 114 (35) ◽  
pp. 9421-9426 ◽  
Author(s):  
Rachel Larder ◽  
M. F. Michelle Sim ◽  
Pawan Gulati ◽  
Robin Antrobus ◽  
Y. C. Loraine Tung ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
High Fat Diet ◽  
Molecular Mechanisms ◽  
Nuclear Pore ◽  
Chromosome 2 ◽  
Body Weight Regulation ◽  
Wild Type ◽  
The Central Nervous System ◽  
The Impact

An intergenic region of human chromosome 2 (2p25.3) harbors genetic variants which are among those most strongly and reproducibly associated with obesity. The gene closest to these variants is TMEM18, although the molecular mechanisms mediating these effects remain entirely unknown. Tmem18 expression in the murine hypothalamic paraventricular nucleus (PVN) was altered by changes in nutritional state. Germline loss of Tmem18 in mice resulted in increased body weight, which was exacerbated by high fat diet and driven by increased food intake. Selective overexpression of Tmem18 in the PVN of wild-type mice reduced food intake and also increased energy expenditure. We provide evidence that TMEM18 has four, not three, transmembrane domains and that it physically interacts with key components of the nuclear pore complex. Our data support the hypothesis that TMEM18 itself, acting within the central nervous system, is a plausible mediator of the impact of adjacent genetic variation on human adiposity.

P3399Influence of TCF21 rs12190287 in the coronary artery disease risk prediction. An association study in a Portuguese population

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
J Sousa ◽  
M Mendonca ◽  
A Pereira ◽  
F Mendonca ◽  
J Monteiro ◽  
...  
Keyword(s):  
Risk Score ◽  
Genetic Variants ◽  
Genetic Risk ◽  
Disease Risk ◽  
Smoking Status ◽  
Genetic Risk Score ◽  
Strong Association ◽  
Portuguese Population ◽  
The Impact ◽  
Cad Risk

Abstract TCF21 is a member of the basic-helix-loop-helix (bHLH) transcriptor factor family, being critical for embryogenesis of the heart, kidney and spleen. TCF21 also regulates epicardium-derived cells differentiation into smooth muscle and fibroblast lineages. Aim Investigate the impact of TCF21 rs12190287 in the prediction and discrimination of CAD risk, individually or into a genetic risk score (GRS) formed by a set of 13 genetic variants. Methods We performed a case-control study with 3050 subjects (1619 coronary patients with 53.3±8 years; 78.9% male and 1431 controls with 52.8±8 years; 76.6% male) from GENEMACOR study. We investigated all traditional risk factors (TRF), as well as 13 genetic variants from GWAS with unknown pathophysiological pathway so far, including TCF21 (rs12190287), ZC3HC1 (rs11556924), PSRC1/SORTI (rs599839), PHACTR1 (rs1332844), MIA3 (rs17465637), SMAD3 (rs17228212), ZNF259 (rs964184), ADAMTS7 (rs3825807), CDKN2B (rs4977574), 9p21.3 (rs1333049), KIF6 (rs20455), PCSK9 (rs2114580) and GJA4 (rs618675). A multiplicative genetic risk score with these 13 genetic variants (m13GRS), was calculated. Subsequently, two logistic regressions were performed; primarily with all the TRF and all the genes individually and the second with TRF and m13GRS. Results The first multivariate analysis shows that, besides the strong association of the TRF with CAD risk (with smoking status on the top of the list, with an OR of 3.2; p<0.0001), TCF21 rs12190287 was the most significant variant from all the studied genetic set with a CAD risk of 1.5 (95% CI: 1.1–1.9; p=0.004), followed by the well-known genetic determinant CDKN2B rs4977574 (OR=1.4; 95% CI: 1.1–1.7; p<0.002) and ZC3HC1 rs11556924 (OR=1.3; 95% CI: 1.0–1.7; p=0.034). When GRS is included to the model, all the TRF remain in the equation by the same order, and the m13GRS persisted as an independent predictor for CAD risk (OR=1.7; 95% CI: 1.4–2.0; p<0.0001). Conclusion TCF21 rs12190287 is a risk factor for CAD in the Portuguese population, either individually or incorporated in a m13GRS. TCF21 risk is independent from TRF. In the future, TCF21 can provide a new clues to identify patients at high cardiovascular risk and become a potential target for gene therapy.

scholarly journals The Primary Enveloped Virion of Herpes Simplex Virus 1: Its Role in Nuclear Egress

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
Author(s):  
William W. Newcomb ◽  
Juan Fontana ◽  
Dennis C. Winkler ◽  
Naiqian Cheng ◽  
J. Bernard Heymann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Nuclear Membrane ◽  
Molecular Mechanisms ◽  
Weak Interactions ◽  
Nuclear Pore ◽  
Nuclear Egress ◽  
Cryo Electron Microscopy ◽  
Perinuclear Space ◽  
Infected Cells ◽  
Hsv 1

ABSTRACTMany viruses migrate between different cellular compartments for successive stages of assembly. The HSV-1 capsid assembles in the nucleus and then transfers into the cytoplasm. First, the capsid buds through the inner nuclear membrane, becoming coated with nuclear egress complex (NEC) protein. This yields a primary enveloped virion (PEV) whose envelope fuses with the outer nuclear membrane, releasing the capsid into the cytoplasm. We investigated the associated molecular mechanisms by isolating PEVs from US3-null-infected cells and imaging them by cryo-electron microscopy and tomography. (pUS3 is a viral protein kinase in whose absence PEVs accumulate in the perinuclear space.) Unlike mature extracellular virions, PEVs have very few glycoprotein spikes. PEVs are ~20% smaller than mature virions, and the little space available between the capsid and the NEC layer suggests that most tegument proteins are acquired later in the egress pathway. Previous studies have proposed that NEC is organized as hexamers in honeycomb arrays in PEVs, but we find arrays of heptameric rings in extracts from US3-null-infected cells. In a PEV, NEC contacts the capsid predominantly via the pUL17/pUL25 complexes which are located close to the capsid vertices. Finally, the NEC layer dissociates from the capsid as it leaves the nucleus, possibly in response to pUS3-mediated phosphorylation. Overall, nuclear egress emerges as a process driven by a program of multiple weak interactions.IMPORTANCEOn its maturation pathway, the newly formed HSV-1 nucleocapsid must traverse the nuclear envelope, while respecting the integrity of that barrier. Nucleocapsids (125 nm in diameter) are too large to pass through the nuclear pore complexes that conduct most nucleocytoplasmic traffic. It is now widely accepted that the process involves envelopment/de-envelopment of a key intermediate—the primary enveloped virion. In wild-type infections, PEVs are short-lived, which has impeded study. Using a mutant that accumulates PEVs in the perinuclear space, we were able to isolate PEVs in sufficient quantity for structural analysis by cryo-electron microscopy and tomography. The findings not only elucidate the maturation pathway of an important human pathogen but also have implications for cellular processes that involve the trafficking of large macromolecular complexes.

scholarly journals Associations between dairy consumption and body weight: a review of the evidence and underlying mechanisms

2011 ◽  
Vol 24 (1) ◽  
pp. 72-95 ◽  
Author(s):  
Anestis Dougkas ◽  
Christopher K. Reynolds ◽  
Ian D. Givens ◽  
Peter C. Elwood ◽  
Anne M. Minihane
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Food Intake ◽  
Molecular Mechanisms ◽  
Dairy Product ◽  
Energy Restriction ◽  
Appetite Regulation ◽  
Dairy Consumption ◽  
Underlying Mechanisms ◽  
The Impact

As the incidence of obesity is reaching ‘epidemic’ proportions, there is currently widespread interest in the impact of dietary components on body-weight and food intake regulation. The majority of data available from both epidemiological and intervention studies provide evidence of a negative but modest association between milk and dairy product consumption and BMI and other measures of adiposity, with indications that higher intakes result in increased weight loss and lean tissue maintenance during energy restriction. The purported physiological and molecular mechanisms underlying the impact of dairy constituents on adiposity are incompletely understood but may include effects on lipolysis, lipogeneis and fatty acid absorption. Furthermore, accumulating evidence indicates an impact of dairy constituents, in particular whey protein derivatives, on appetite regulation and food intake. The present review summarises available data and provides an insight into the likely contribution of dairy foods to strategies aimed at appetite regulation, weight loss or the prevention of weight gain.

scholarly journals In Pursuit of Distinctiveness: Transmembrane Nucleoporins and Their Disease Associations

2021 ◽  
Vol 11 ◽  
Author(s):  
Divya Bindra ◽  
Ram Kumar Mishra
Keyword(s):  
Nuclear Membrane ◽  
Cell Cycle Control ◽  
Strong Association ◽  
Nuclear Pore ◽  
Cellular Functions ◽  
Cellular Processes ◽  
Damage Repair ◽  
Disease Associations ◽  
Multiple Copies ◽  
Underlying Mechanisms

The bi-directional nucleocytoplasmic shuttling of macromolecules like molecular signals, transcription factors, regulatory proteins, and RNAs occurs exclusively through Nuclear Pore Complex (NPC) residing in the nuclear membrane. This magnanimous complex is essentially a congregation of ~32 conserved proteins termed Nucleoporins (Nups) present in multiple copies and mostly arranged as subcomplexes to constitute a functional NPC. Nups participate in ancillary functions such as chromatin organization, transcription regulation, DNA damage repair, genome stabilization, and cell cycle control, apart from their central role as nucleocytoplasmic conduits. Thus, Nups exert a role in the maintenance of cellular homeostasis. In mammals, precisely three nucleoporins traverse the nuclear membrane, are called transmembrane Nups (TM-Nups), and are involved in multiple cellular functions. Owing to their vital roles in cellular processes and homeostasis, dysregulation of nucleoporin function is implicated in various diseases. The deregulated functioning of TM-Nups can thus act as an opportune window for the development of diseases. Indeed, mounting evidence exhibits a strong association of TM-Nups in cancer and numerous other physiological disorders. These findings have provided much-needed insights into the novel mechanisms of disease progression. While nucleoporin’s functions have often been summarized in the disease context, a focus on TM-Nups has always lacked. This review emphasizes the elucidation of distinct canonical and non-canonical functions of mammalian TM-Nups and the underlying mechanisms of their disease association.

Use of genetic variants in c-MET to predict clinical outcome in localized gastric cancer (GC) patients (pts) treated with surgery.

2014 ◽  
Vol 32 (3_suppl) ◽  
pp. 50-50
Author(s):  
Yu Sunakawa ◽  
Takeru Wakatsuki ◽  
Wu Zhang ◽  
Dongyun Yang ◽  
Mizutomo Azuma ◽  
...  
Keyword(s):  
Adjuvant Therapy ◽  
Clinical Outcome ◽  
Clinical Outcomes ◽  
Genetic Variants ◽  
Molecular Mechanisms ◽  
Univariate Analysis ◽  
Candidate Snps ◽  
Prognostic Impact ◽  
Wide Range ◽  
The Impact

50 Background: Dysregulation of the c-MET signaling pathway occurs in a wide range of human cancers including GC. Such derangements result from various molecular mechanisms, including mutations, amplification and overexpression of c-MET. Overexpression and amplification of c-MET have been correlated with poor clinical outcomes in pts with GC. However, the association between c-MET polymorphisms and prognosis in GC is not well defined. We examined the prognostic impact of c-MET polymorphisms on clinical outcomes in pts with localized GC treated with surgery. Methods: One-hundred and sixty-one Japanese pts were included, with localized GC (stage Ib-IV) treated with surgery alone (n=58), or surgery plus adjuvant therapy (n=103) between 2002 and 2010. Median follow up was 4 years. Genomic DNA was extracted from the pts’ blood or tissue. Six functionally significant c-MET SNPs (rs1621, rs40239, rs41736, rs41739, rs184953, rs10234854) were analyzed by PCR-based direct sequencing. All candidate SNPs were analyzed for association with disease free survival (DFS) and overall survival (OS) by uni- and multivariate analyses, adjusting for age, sex, stage and type of adjuvant therapy. Results: The MET rs40239 variant was associated with favorable clinical outcomes. Univariate analysis showed pts with any G (AG/GG) allele had significantly longer DFS and OS compared to those with the AA genotype (HR: 0.43; 95% CI: 0.25-0.74; P=0.001, HR: 0.47; 95% CI: 0.27-0.81; P=0.006, log-rank test, respectively); this remained significant upon multivariate analysis (HR: 0.48; 95% CI: 0.27-0.83; P=0.009, HR: 0.50; 95% CI: 0.28-0.88; P=0.017, respectively). In the subgroup analysis by gender, men, but not women, with the AG/GG genotypes maintained a DFS and OS benefit. Conclusions: Our results show for the first time that the c-MET polymorphism, rs40239, may serve as a prognostic marker in pts with localized GC treated with surgery. There also appears to be a gender-related difference in the impact on clinical outcome by genetic variants of c-MET. Prospective validation of this study is warranted.

scholarly journals Familial Arrhythmogenic Cardiomyopathy: Clinical Determinants of Phenotype Discordance and the Impact of Endurance Sports

2020 ◽  
Vol 9 (11) ◽  
pp. 3781
Author(s):  
Sarah Costa ◽  
Alessio Gasperetti ◽  
Argelia Medeiros-Domingo ◽  
Deniz Akdis ◽  
Corinna Brunckhorst ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Phenotypic Expression ◽  
Clinical Manifestations ◽  
Incomplete Penetrance ◽  
Common Denominator ◽  
Arrhythmogenic Cardiomyopathy ◽  
Variable Expression ◽  
The Impact

Arrhythmogenic cardiomyopathy (ACM) is primarily a familial disease with autosomal dominant inheritance. Incomplete penetrance and variable expression are common, resulting in diverse clinical manifestations. Although recent studies on genotype–phenotype relationships have improved our understanding of the molecular mechanisms leading to the expression of the full-blown disease, the underlying genetic substrate and the clinical course of asymptomatic or oligo-symptomatic mutation carriers are still poorly understood. We aimed to analyze different phenotypic expression profiles of ACM in the context of the same familial genetic mutation by studying nine adult cases from four different families with four different familial variants (two plakophilin-2 and two desmoglein-2) from the Swiss Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Registry. The affected individuals with the same genetic variants presented with highly variable phenotypes ranging from no disease or a classical, right-sided disease, to ACM with biventricular presentation. Moreover, some patients developed early-onset, electrically unstable disease whereas others with the same genetic variants presented with late-onset electrically stable disease. Despite differences in age, gender, underlying genotype, and other clinical characteristics, physical exercise has been observed as the common denominator in provoking an arrhythmic phenotype in these families.

scholarly journals POM121 and Sun1 play a role in early steps of interphase NPC assembly

2011 ◽  
Vol 194 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Jessica A. Talamas ◽  
Martin W. Hetzer
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Molecular Mechanisms ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Outer Nuclear Membrane ◽  
Nuclear Membranes ◽  
Distinct Cell ◽  
Pore Complexes

Nuclear pore complexes (NPCs) assemble at the end of mitosis during nuclear envelope (NE) reformation and into an intact NE as cells progress through interphase. Although recent studies have shown that NPC formation occurs by two different molecular mechanisms at two distinct cell cycle stages, little is known about the molecular players that mediate the fusion of the outer and inner nuclear membranes to form pores. In this paper, we provide evidence that the transmembrane nucleoporin (Nup), POM121, but not the Nup107–160 complex, is present at new pore assembly sites at a time that coincides with inner nuclear membrane (INM) and outer nuclear membrane (ONM) fusion. Overexpression of POM121 resulted in juxtaposition of the INM and ONM. Additionally, Sun1, an INM protein that is known to interact with the cytoskeleton, was specifically required for interphase assembly and localized with POM121 at forming pores. We propose a model in which POM121 and Sun1 interact transiently to promote early steps of interphase NPC assembly.

The Formation, Structure, Distribution and Frequency of Nuclear Pores

1971 ◽  
Vol 29 ◽  
pp. 518-519
Author(s):  
G. G. Maul
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Dynamic Structure ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Filter Function ◽  
Etching Technique ◽  
Selective Filter ◽  
Membranous Part

The chromatin of eukaryotic cells is separated from the cytoplasm by a double membrane. One obvious structural specialization of the nuclear membrane is the presence of pores which have been implicated to facilitate the selective nucleocytoplasmic exchange of a variety of large molecules. Thus, the function of nuclear pores has mainly been regarded to be a passive one. Non-membranous diaphragms, radiating fibers, central rings, and other pore-associated structures were thought to play a role in the selective filter function of the nuclear pore complex. Evidence will be presented that suggests that the nuclear pore is a dynamic structure which is non-randomly distributed and can be formed during interphase, and that a close relationship exists between chromatin and the membranous part of the nuclear pore complex.Octagonality of the nuclear pore complex has been confirmed by a variety of techniques. Using the freeze-etching technique, it was possible to show that the membranous part of the pore complex has an eight-sided outline in human melanoma cells in vitro. Fibers which traverse the pore proper at its corners are continuous and indistinguishable from chromatin at the nucleoplasmic side, as seen in conventionally fixed and sectioned material. Chromatin can be seen in octagonal outline if serial sections are analyzed which are parallel but do not include nuclear membranes (Fig. 1). It is concluded that the shape of the pore rim is due to fibrous material traversing the pore, and may not have any functional significance. In many pores one can recognize a central ring with eight fibers radiating to the corners of the pore rim. Such a structural arrangement is also found to connect eight ribosomes at the nuclear membrane.

Genetic Variation: Impact on Folate (and Choline) Bioefficacy

2010 ◽  
Vol 80 (45) ◽  
pp. 319-329 ◽  
Author(s):  
Allyson A. West ◽  
Marie A. Caudill
Keyword(s):  
Carbon Metabolism ◽  
Genetic Variants ◽  
Plasma Homocysteine ◽  
Water Soluble ◽  
Gene Interactions ◽  
Dietary Folate ◽  
Methyl Donors ◽  
Common Genetic Variants ◽  
One Carbon Metabolism ◽  
The Impact

Folate and choline are water-soluble micronutrients that serve as methyl donors in the conversion of homocysteine to methionine. Inadequacy of these nutrients can disturb one-carbon metabolism as evidenced by alterations in circulating folate and/or plasma homocysteine. Among common genetic variants that reside in genes regulating folate absorptive and metabolic processes, homozygosity for the MTHFR 677C > T variant has consistently been shown to have robust effects on status markers. This paper will review the impact of genetic variants in folate-metabolizing genes on folate and choline bioefficacy. Nutrient-gene and gene-gene interactions will be considered along with the need to account for these genetic variants when updating dietary folate and choline recommendations.

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