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1.
Nature ; 502(7470): 228-31, 2013 Oct 10.
Article in English | MEDLINE | ID: mdl-24005325

ABSTRACT

Evolution is typically thought to proceed through divergence of genes, proteins and ultimately phenotypes. However, similar traits might also evolve convergently in unrelated taxa owing to similar selection pressures. Adaptive phenotypic convergence is widespread in nature, and recent results from several genes have suggested that this phenomenon is powerful enough to also drive recurrent evolution at the sequence level. Where homoplasious substitutions do occur these have long been considered the result of neutral processes. However, recent studies have demonstrated that adaptive convergent sequence evolution can be detected in vertebrates using statistical methods that model parallel evolution, although the extent to which sequence convergence between genera occurs across genomes is unknown. Here we analyse genomic sequence data in mammals that have independently evolved echolocation and show that convergence is not a rare process restricted to several loci but is instead widespread, continuously distributed and commonly driven by natural selection acting on a small number of sites per locus. Systematic analyses of convergent sequence evolution in 805,053 amino acids within 2,326 orthologous coding gene sequences compared across 22 mammals (including four newly sequenced bat genomes) revealed signatures consistent with convergence in nearly 200 loci. Strong and significant support for convergence among bats and the bottlenose dolphin was seen in numerous genes linked to hearing or deafness, consistent with an involvement in echolocation. Unexpectedly, we also found convergence in many genes linked to vision: the convergent signal of many sensory genes was robustly correlated with the strength of natural selection. This first attempt to detect genome-wide convergent sequence evolution across divergent taxa reveals the phenomenon to be much more pervasive than previously recognized.


Subject(s)
Biological Evolution , Chiroptera/classification , Chiroptera/genetics , Dolphins/classification , Dolphins/genetics , Echolocation , Genome/genetics , Animals , Hearing/genetics , Phylogeny , Selection, Genetic , Vision, Ocular/genetics
2.
Proc Natl Acad Sci U S A ; 113(51): E8286-E8295, 2016 12 20.
Article in English | MEDLINE | ID: mdl-27930306

ABSTRACT

Invariant natural killer T cells (iNKT) cells are T lymphocytes displaying innate effector functions, acquired through a distinct thymic developmental program regulated by microRNAs (miRNAs). Deleting miRNAs by Dicer ablation (Dicer KO) in thymocytes selectively impairs iNKT cell survival and functional differentiation. To unravel this miRNA-dependent program, we systemically identified transcripts that were differentially expressed between WT and Dicer KO iNKT cells at different differentiation stages and predicted to be targeted by the iNKT cell-specific miRNAs. TGF-ß receptor II (TGF-ßRII), critically implicated in iNKT cell differentiation, was found up-regulated in iNKT Dicer KO cells together with enhanced TGF-ß signaling. miRNA members of the miR-17∼92 family clusters were predicted to target Tgfbr2 mRNA upon iNKT cell development. iNKT cells lacking all three miR-17∼92 family clusters (miR-17∼92, miR-106a∼363, miR-106b∼25) phenocopied both increased TGF-ßRII expression and signaling, and defective effector differentiation, displayed by iNKT Dicer KO cells. Consistently, genetic ablation of TGF-ß signaling in the absence of miRNAs rescued iNKT cell differentiation. These results elucidate the global impact of miRNAs on the iNKT cell developmental program and uncover the targeting of a lineage-specific cytokine signaling by miRNAs as a mechanism regulating innate-like T-cell development and effector differentiation.


Subject(s)
MicroRNAs/genetics , Natural Killer T-Cells/cytology , Transforming Growth Factor beta/metabolism , Animals , Antigens, CD1d/metabolism , Cell Differentiation , Cytokines/metabolism , DEAD-box RNA Helicases/genetics , Gene Expression Profiling , Genetic Complementation Test , Mice , Mice, Inbred C57BL , Mice, Knockout , Multigene Family , Phenotype , RNA, Messenger/metabolism , Ribonuclease III/genetics , Signal Transduction , Thymus Gland/metabolism
3.
Nature ; 491(7424): 454-7, 2012 Nov 15.
Article in English | MEDLINE | ID: mdl-23064229

ABSTRACT

Most of the mammalian genome is transcribed. This generates a vast repertoire of transcripts that includes protein-coding messenger RNAs, long non-coding RNAs (lncRNAs) and repetitive sequences, such as SINEs (short interspersed nuclear elements). A large percentage of ncRNAs are nuclear-enriched with unknown function. Antisense lncRNAs may form sense-antisense pairs by pairing with a protein-coding gene on the opposite strand to regulate epigenetic silencing, transcription and mRNA stability. Here we identify a nuclear-enriched lncRNA antisense to mouse ubiquitin carboxy-terminal hydrolase L1 (Uchl1), a gene involved in brain function and neurodegenerative diseases. Antisense Uchl1 increases UCHL1 protein synthesis at a post-transcriptional level, hereby identifying a new functional class of lncRNAs. Antisense Uchl1 activity depends on the presence of a 5' overlapping sequence and an embedded inverted SINEB2 element. These features are shared by other natural antisense transcripts and can confer regulatory activity to an artificial antisense to green fluorescent protein. Antisense Uchl1 function is under the control of stress signalling pathways, as mTORC1 inhibition by rapamycin causes an increase in UCHL1 protein that is associated to the shuttling of antisense Uchl1 RNA from the nucleus to the cytoplasm. Antisense Uchl1 RNA is then required for the association of the overlapping sense protein-coding mRNA to active polysomes for translation. These data reveal another layer of gene expression control at the post-transcriptional level.


Subject(s)
Protein Biosynthesis/genetics , RNA, Antisense/metabolism , Short Interspersed Nucleotide Elements/genetics , Ubiquitin Thiolesterase/genetics , Ubiquitin Thiolesterase/metabolism , Animals , Anti-Bacterial Agents/pharmacology , Cell Line , Humans , Male , Mice , Protein Biosynthesis/drug effects , RNA, Antisense/genetics , Sequence Inversion , Sirolimus/pharmacology
4.
Clin Immunol ; 178: 20-28, 2017 05.
Article in English | MEDLINE | ID: mdl-26732860

ABSTRACT

Activated PI3-kinase delta syndrome (APDS) was recently reported as a novel primary immunodeficiency caused by heterozygous gain-of-function mutations in PIK3CD gene. Here we describe immunological studies in a 19year old APDS patient for whom genetic diagnosis was discovered by Whole Exome Sequencing (WES) analysis. In addition to the progressive lymphopenia and defective antibody production we showed that the ability of the patient's B cells to differentiate in vitro is severely reduced. An in depth analysis of the myeloid compartment showed an increased expression of CD83 activation marker on monocytes and mono-derived DC cells. Moreover, monocytes-derived macrophages (MDMs) failed to solve the Mycobacterium bovis bacillus Calmette Guèrin (BCG) infection in vitro. Selective p110δ inhibitor IC87114 restored the MDM capacity to kill BCG in vitro. Our data show that the constitutive activation of Akt-mTOR pathway induces important alterations also in the myeloid compartment providing new insights in order to improve the therapeutic approach in these patients.


Subject(s)
B-Lymphocytes/immunology , Cell Differentiation/immunology , Dendritic Cells/immunology , Immunologic Deficiency Syndromes/immunology , Macrophages/immunology , Adenine/analogs & derivatives , Adenine/pharmacology , Cell Differentiation/genetics , Class I Phosphatidylinositol 3-Kinases/genetics , Class I Phosphatidylinositol 3-Kinases/immunology , Humans , Immunologic Deficiency Syndromes/genetics , In Vitro Techniques , Inflammation , Lymphopenia/genetics , Lymphopenia/immunology , Macrophages/drug effects , Male , Mycobacterium bovis/immunology , Primary Immunodeficiency Diseases , Proto-Oncogene Proteins c-akt/immunology , Quinazolines/pharmacology , Signal Transduction , TOR Serine-Threonine Kinases/immunology , Young Adult
5.
Development ; 141(3): 715-24, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24449846

ABSTRACT

Zebrafish transgenesis is increasingly popular owing to the optical transparency and external development of embryos, which provide a scalable vertebrate model for in vivo experimentation. The ability to express transgenes in a tightly controlled spatio-temporal pattern is an important prerequisite for exploitation of zebrafish in a wide range of biomedical applications. However, conventional transgenesis methods are plagued by position effects: the regulatory environment of genomic integration sites leads to variation of expression patterns of transgenes driven by engineered cis-regulatory modules. This limitation represents a bottleneck when studying the precise function of cis-regulatory modules and their subtle variants or when various effector proteins are to be expressed for labelling and manipulation of defined sets of cells. Here, we provide evidence for the efficient elimination of variability of position effects by developing a PhiC31 integrase-based targeting method. To detect targeted integration events, a simple phenotype scoring of colour change in the lens of larvae is used. We compared PhiC31-based integration and Tol2 transgenesis in the analysis of the activity of a novel conserved enhancer from the developmentally regulated neural-specific esrrga gene. Reporter expression was highly variable among independent lines generated with Tol2, whereas all lines generated with PhiC31 into a single integration site displayed nearly identical, enhancer-specific reporter expression in brain nuclei. Moreover, we demonstrate that a modified integrase system can also be used for the detection of enhancer activity in transient transgenesis. These results demonstrate the power of the PhiC31-based transgene integration for the annotation and fine analysis of transcriptional regulatory elements and it promises to be a generally desirable tool for a range of applications, which rely on highly reproducible patterns of transgene activity in zebrafish.


Subject(s)
Chromosomal Position Effects/genetics , Gene Targeting , Mutagenesis, Insertional/genetics , Transgenes/genetics , Zebrafish/genetics , Animals , Animals, Genetically Modified , Base Sequence , Brain/metabolism , Enhancer Elements, Genetic/genetics , Gene Expression Regulation , Gene Transfer Techniques , Genes, Reporter/genetics , Genetic Loci/genetics , Genome/genetics , Integrases/metabolism , Lens, Crystalline/metabolism , Molecular Sequence Data , Reproducibility of Results , Xenopus laevis/genetics
6.
Hum Mol Genet ; 23(10): 2511-26, 2014 May 15.
Article in English | MEDLINE | ID: mdl-24412933

ABSTRACT

Ocular coloboma is a congenital defect resulting from failure of normal closure of the optic fissure during embryonic eye development. This birth defect causes childhood blindness worldwide, yet the genetic etiology is poorly understood. Here, we identified a novel homozygous mutation in the SALL2 gene in members of a consanguineous family affected with non-syndromic ocular coloboma variably affecting the iris and retina. This mutation, c.85G>T, introduces a premature termination codon (p.Glu29*) predicted to truncate the SALL2 protein so that it lacks three clusters of zinc-finger motifs that are essential for DNA-binding activity. This discovery identifies SALL2 as the third member of the Drosophila homeotic Spalt-like family of developmental transcription factor genes implicated in human disease. SALL2 is expressed in the developing human retina at the time of, and subsequent to, optic fissure closure. Analysis of Sall2-deficient mouse embryos revealed delayed apposition of the optic fissure margins and the persistence of an anterior retinal coloboma phenotype after birth. Sall2-deficient embryos displayed correct posterior closure toward the optic nerve head, and upon contact of the fissure margins, dissolution of the basal lamina occurred and PAX2, known to be critical for this process, was expressed normally. Anterior closure was disrupted with the fissure margins failing to meet, or in some cases misaligning leading to a retinal lesion. These observations demonstrate, for the first time, a role for SALL2 in eye morphogenesis and that loss of function of the gene causes ocular coloboma in humans and mice.


Subject(s)
Codon, Nonsense , Coloboma/genetics , Transcription Factors/genetics , Adolescent , Animals , Child , Consanguinity , DNA Mutational Analysis , DNA-Binding Proteins , Eye/embryology , Eye/pathology , Eye Proteins/genetics , Eye Proteins/metabolism , Female , Gene Expression , Genes, Recessive , Genetic Association Studies , Genetic Predisposition to Disease , HEK293 Cells , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Homozygote , Humans , Male , Mice, Inbred C57BL , Mice, Knockout , PAX2 Transcription Factor/genetics , PAX2 Transcription Factor/metabolism , PAX6 Transcription Factor , Paired Box Transcription Factors/genetics , Paired Box Transcription Factors/metabolism , Pedigree , Polymorphism, Single Nucleotide , Repressor Proteins/genetics , Repressor Proteins/metabolism , Transcription Factors/metabolism
7.
Genome Res ; 23(11): 1938-50, 2013 Nov.
Article in English | MEDLINE | ID: mdl-24002785

ABSTRACT

Spatiotemporal control of gene expression is central to animal development. Core promoters represent a previously unanticipated regulatory level by interacting with cis-regulatory elements and transcription initiation in different physiological and developmental contexts. Here, we provide a first and comprehensive description of the core promoter repertoire and its dynamic use during the development of a vertebrate embryo. By using cap analysis of gene expression (CAGE), we mapped transcription initiation events at single nucleotide resolution across 12 stages of zebrafish development. These CAGE-based transcriptome maps reveal genome-wide rules of core promoter usage, structure, and dynamics, key to understanding the control of gene regulation during vertebrate ontogeny. They revealed the existence of multiple classes of pervasive intra- and intergenic post-transcriptionally processed RNA products and their developmental dynamics. Among these RNAs, we report splice donor site-associated intronic RNA (sRNA) to be specific to genes of the splicing machinery. For the identification of conserved features, we compared the zebrafish data sets to the first CAGE promoter map of Tetraodon and the existing human CAGE data. We show that a number of features, such as promoter type, newly discovered promoter properties such as a specialized purine-rich initiator motif, as well as sRNAs and the genes in which they are detected, are conserved in mammalian and Tetraodon CAGE-defined promoter maps. The zebrafish developmental promoterome represents a powerful resource for studying developmental gene regulation and revealing promoter features shared across vertebrates.


Subject(s)
Embryonic Development/genetics , Gene Expression Regulation, Developmental , Purines/metabolism , Transcription Initiation Site , Zebrafish/embryology , Zebrafish/genetics , Animals , Evolution, Molecular , Gene Expression Profiling , Genes , Genome , Phylogeny , Promoter Regions, Genetic , RNA/genetics , RNA/metabolism , RNA Caps/genetics , RNA Splicing , Transcriptome , Vertebrates/genetics
8.
J Med Genet ; 52(3): 147-56, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25564561

ABSTRACT

BACKGROUND: Mutations in microtubule-regulating genes are associated with disorders of neuronal migration and microcephaly. Regulation of centriole length has been shown to underlie the pathogenesis of certain ciliopathy phenotypes. Using a next-generation sequencing approach, we identified mutations in a novel centriolar disease gene in a kindred with an embryonic lethal ciliopathy phenotype and in a patient with primary microcephaly. METHODS AND RESULTS: Whole exome sequencing data from a non-consanguineous Caucasian kindred exhibiting mid-gestation lethality and ciliopathic malformations revealed two novel non-synonymous variants in CENPF, a microtubule-regulating gene. All four affected fetuses showed segregation for two mutated alleles [IVS5-2A>C, predicted to abolish the consensus splice-acceptor site from exon 6; c.1744G>T, p.E582X]. In a second unrelated patient exhibiting microcephaly, we identified two CENPF mutations [c.1744G>T, p.E582X; c.8692 C>T, p.R2898X] by whole exome sequencing. We found that CENP-F colocalised with Ninein at the subdistal appendages of the mother centriole in mouse inner medullary collecting duct cells. Intraflagellar transport protein-88 (IFT-88) colocalised with CENP-F along the ciliary axonemes of renal epithelial cells in age-matched control human fetuses but did not in truncated cilia of mutant CENPF kidneys. Pairwise co-immunoprecipitation assays of mitotic and serum-starved HEKT293 cells confirmed that IFT88 precipitates with endogenous CENP-F. CONCLUSIONS: Our data identify CENPF as a new centriolar disease gene implicated in severe human ciliopathy and microcephaly related phenotypes. CENP-F has a novel putative function in ciliogenesis and cortical neurogenesis.


Subject(s)
Chromosomal Proteins, Non-Histone/genetics , Cilia/genetics , Genetics, Medical , Microcephaly/genetics , Microfilament Proteins/genetics , Animals , Centrioles/genetics , Cilia/pathology , Exome/genetics , Female , Fetus , HEK293 Cells , High-Throughput Nucleotide Sequencing , Humans , Male , Mice , Microcephaly/pathology , Mutation , NIH 3T3 Cells , Pedigree , Pregnancy , Zebrafish
9.
Nucleic Acids Res ; 42(12): 7793-806, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24895435

ABSTRACT

Vertebrate organogenesis is critically sensitive to gene dosage and even subtle variations in the expression levels of key genes may result in a variety of tissue anomalies. MicroRNAs (miRNAs) are fundamental regulators of gene expression and their role in vertebrate tissue patterning is just beginning to be elucidated. To gain further insight into this issue, we analysed the transcriptomic consequences of manipulating the expression of miR-204 in the Medaka fish model system. We used RNA-Seq and an innovative bioinformatics approach, which combines conventional differential expression analysis with the behavior expected by miR-204 targets after its overexpression and knockdown. With this approach combined with a correlative analysis of the putative targets, we identified a wider set of miR-204 target genes belonging to different pathways. Together, these approaches confirmed that miR-204 has a key role in eye development and further highlighted its putative function in neural differentiation processes, including axon guidance as supported by in vivo functional studies. Together, our results demonstrate the advantage of integrating next-generation sequencing and bioinformatics approaches to investigate miRNA biology and provide new important information on the role of miRNAs in the control of axon guidance and more broadly in nervous system development.


Subject(s)
Axons/physiology , Gene Expression Profiling , MicroRNAs/metabolism , Neurogenesis/genetics , Oryzias/genetics , Animals , Axons/ultrastructure , Computational Biology , Gene Knockdown Techniques , High-Throughput Nucleotide Sequencing , Models, Animal , Oryzias/embryology , Oryzias/metabolism , Retina/embryology , Retina/metabolism , Retina/ultrastructure , Sequence Analysis, RNA
10.
J Cell Sci ; 126(Pt 10): 2236-45, 2013 May 15.
Article in English | MEDLINE | ID: mdl-23525014

ABSTRACT

Overexpression of facioscapulohumeral muscular dystrophy region gene 1 (FRG1) in mice, frogs and worms leads to muscular and vascular abnormalities. Nevertheless, the mechanism that follows FRG1 overexpression and finally leads to muscular defects is currently unknown. Here, we show that the earliest phenotype displayed by mice overexpressing FRG1 is a postnatal muscle-growth defect. Long before the development of muscular dystrophy, FRG1 mice also exhibit a muscle regeneration impairment. Ex vivo and in vivo experiments revealed that FRG1 overexpression causes myogenic stem cell activation and proliferative, clonogenic and differentiation defects. A comparative gene expression profiling of muscles from young pre-dystrophic wild-type and FRG1 mice identified differentially expressed genes in several gene categories and networks that could explain the emerging tissue and myogenic stem cell defects. Overall, our study provides new insights into the pathways regulated by FRG1 and suggests that muscle stem cell defects could contribute to the pathology of FRG1 mice.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Autoimmune Diseases/metabolism , Carrier Proteins/metabolism , Cell Surface Extensions/physiology , Cytoskeletal Proteins/metabolism , Macrophages/physiology , Multipotent Stem Cells/physiology , Muscular Dystrophy, Facioscapulohumeral/metabolism , Actin Cytoskeleton/metabolism , Adaptor Proteins, Signal Transducing/genetics , Animals , Carrier Proteins/genetics , Cell Line , Cytoskeletal Proteins/genetics , Fatty Acid-Binding Proteins , Mice , Muscle Development/genetics , Protein Multimerization/genetics , Protein Structure, Tertiary/genetics , RNA, Small Interfering/genetics , Transgenes/genetics , Wiskott-Aldrich Syndrome Protein/metabolism
11.
Blood ; 121(8): 1265-75, 2013 Feb 21.
Article in English | MEDLINE | ID: mdl-23169781

ABSTRACT

The role of forkhead box P3 (FOXP3) is well-established in T-regulatory cells, but the function of transient FOXP3 expression in activated human conventional T (Tconv) cells is unknown. In the present study, we used 2 approaches to determine the role of FOXP3 in human Tconv cells. First, we obtained Tconv clones from a female subject who is hemizygous for a null mutation in FOXP3, allowing the comparison of autologous T-cell clones that do or do not express FOXP3. Second, we knocked down activation-induced FOXP3 in Tconv cells from healthy donors with small interfering RNAagainst FOXP3. We found that FOXP3-deficient Tconv cells proliferate more and produce more cytokines than wild-type Tconv cells and have differential expression of 274 genes. We also investigated the role of FOXP3 in Th1 and Th17 cells and found that the expression of activation-induced FOXP3 was higher and more sustained in Th17 cells compared with Th1 cells. Knocking down FOXP3 expression in Th17 cells significantly increased the production of IFN-γ and decreased the expression of CCR4, but had no effect on IL-17 expression. These data reveal a novel function of FOXP3 in Tconv cells and suggest that expression of this protein is important in the function of multiple CD4(+) T-cell lineages.


Subject(s)
Forkhead Transcription Factors/genetics , Forkhead Transcription Factors/physiology , Th1 Cells/physiology , Th17 Cells/physiology , CD4-Positive T-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/physiology , Cell Lineage/immunology , Cell Proliferation , Clone Cells/cytology , Clone Cells/physiology , Female , Forkhead Transcription Factors/metabolism , Gene Expression Regulation/immunology , Humans , Interferon-gamma/metabolism , Interleukin-2/metabolism , Male , RNA, Small Interfering , Receptors, CCR4/genetics , Receptors, CCR4/metabolism , Th1 Cells/metabolism , Th17 Cells/metabolism , Transcriptome
12.
Nucleic Acids Res ; 41(6): 3600-18, 2013 Apr 01.
Article in English | MEDLINE | ID: mdl-23393190

ABSTRACT

Co-option of cis-regulatory modules has been suggested as a mechanism for the evolution of expression sites during development. However, the extent and mechanisms involved in mobilization of cis-regulatory modules remains elusive. To trace the history of non-coding elements, which may represent candidate ancestral cis-regulatory modules affirmed during chordate evolution, we have searched for conserved elements in tunicate and vertebrate (Olfactores) genomes. We identified, for the first time, 183 non-coding sequences that are highly conserved between the two groups. Our results show that all but one element are conserved in non-syntenic regions between vertebrate and tunicate genomes, while being syntenic among vertebrates. Nevertheless, in all the groups, they are significantly associated with transcription factors showing specific functions fundamental to animal development, such as multicellular organism development and sequence-specific DNA binding. The majority of these regions map onto ultraconserved elements and we demonstrate that they can act as functional enhancers within the organism of origin, as well as in cross-transgenesis experiments, and that they are transcribed in extant species of Olfactores. We refer to the elements as 'Olfactores conserved non-coding elements'.


Subject(s)
Enhancer Elements, Genetic , Gene Expression Regulation, Developmental , Urochordata/genetics , Vertebrates/genetics , Animals , Base Sequence , Conserved Sequence , Dogs , Fishes/genetics , Gene Regulatory Networks , Genes, Homeobox , Genetic Loci , Genome , Humans , Mammals/genetics , Mice , Synteny , Transcription, Genetic
13.
Bioethics ; 29(8): 580-7, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25644664

ABSTRACT

Recent evidence of intergenerational epigenetic programming of disease risk broadens the scope of public health preventive interventions to future generations, i.e. non existing people. Due to the transmission of epigenetic predispositions, lifestyles such as smoking or unhealthy diet might affect the health of populations across several generations. While public policy for the health of future generations can be justified through impersonal considerations, such as maximizing aggregate well-being, in this article we explore whether there are rights-based obligations supervening on intergenerational epigenetic programming despite the non-identity argument, which challenges this rationale in case of policies that affect the number and identity of future people. We propose that rights based obligations grounded in the interests of non-existing people might fall upon existing people when generations overlap. In particular, if environmental exposure in F0 (i.e. existing people) will affect the health of F2 (i.e. non-existing people) through epigenetic programming, then F1 (i.e. existing and overlapping with both F0 and F2) might face increased costs to address F2's condition in the future: this might generate obligations upon F0 from various distributive principles, such as the principle of equal opportunity for well being.


Subject(s)
Environmental Exposure , Epigenesis, Genetic , Gene-Environment Interaction , Genetic Predisposition to Disease , Health Policy , Intergenerational Relations , Life Style , Moral Obligations , Social Responsibility , Epigenomics , Feeding Behavior , Health Policy/trends , Health Status , Humans , Personal Autonomy , Public Policy/trends , Smoking/adverse effects
14.
Hum Mol Genet ; 21(19): 4253-69, 2012 Oct 01.
Article in English | MEDLINE | ID: mdl-22752307

ABSTRACT

Disruption of E-cadherin (CDH1 gene) expression, subcellular localization or function arises during initiation and progression of almost 90% of all epithelial carcinomas. Nevertheless, the mechanisms through which this occurs are largely unknown. Previous studies showed the importance of CDH1 intron 2 sequences for proper gene and protein expression, supporting these as E-cadherin cis-modulators. Through RACE and RT-PCR, we searched for transcription events arising from CDH1 intron 2 and discovered several new transcripts. One, named CDH1a, with high expression in spleen and absent from normal stomach, was demonstrated to be translated into a novel isoform, differing from canonical E-cadherin in its N-terminal, as determined by mass spectrometry. Quantitative and functional assays showed that when overexpressed in an E-cadherin negative context, CDH1a replaced canonical protein interactions and functions. However, when co-expressed with canonical E-cadherin, CDH1a increased cell invasion and angiogenesis. Further, interferon-induced gene IFITM1 and IFI27 levels were increased upon CDH1a overexpression. Effects on invasion and IFITM1 and IFI27 expression were reverted upon CDH1a-specific knockdown. Importantly, CDH1a was de novo expressed in gastric cancer cell lines. This study presents a new mechanism by which E-cadherin functions are impaired by cis-regulatory mechanisms possibly with the involvement of inflammatory machinery. If confirmed in other cancer models, our data enclose potential for designing targeted therapies to rescue E-cadherin function.


Subject(s)
Cadherins/genetics , Cadherins/metabolism , Introns , Stomach Neoplasms/genetics , Stomach Neoplasms/pathology , Transcription, Genetic , Up-Regulation , Animals , Antigens, CD , Cell Line, Tumor , Chick Embryo , Gene Expression Regulation, Neoplastic , Humans , Neoplasm Invasiveness , Neovascularization, Pathologic , Protein Isoforms/genetics , Protein Isoforms/metabolism , Stomach Neoplasms/metabolism
15.
Genome Res ; 21(4): 515-24, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21324880

ABSTRACT

Aberrant DNA methylation (DNAm) was first linked to cancer over 25 yr ago. Since then, many studies have associated hypermethylation of tumor suppressor genes and hypomethylation of oncogenes to the tumorigenic process. However, most of these studies have been limited to the analysis of promoters and CpG islands (CGIs). Recently, new technologies for whole-genome DNAm (methylome) analysis have been developed, enabling unbiased analysis of cancer methylomes. By using MeDIP-seq, we report a sequencing-based comparative methylome analysis of malignant peripheral nerve sheath tumors (MPNSTs), benign neurofibromas, and normal Schwann cells. Analysis of these methylomes revealed a complex landscape of DNAm alterations. In contrast to what has been reported for other tumor types, no significant global hypomethylation was observed in MPNSTs using methylome analysis by MeDIP-seq. However, a highly significant (P < 10(-100)) directional difference in DNAm was found in satellite repeats, suggesting these repeats to be the main target for hypomethylation in MPNSTs. Comparative analysis of the MPNST and Schwann cell methylomes identified 101,466 cancer-associated differentially methylated regions (cDMRs). Analysis showed these cDMRs to be significantly enriched for two satellite repeat types (SATR1 and ARLα) and suggests an association between aberrant DNAm of these sequences and transition from healthy cells to malignant disease. Significant enrichment of hypermethylated cDMRs in CGI shores (P < 10(-60)), non-CGI-associated promoters (P < 10(-4)) and hypomethylated cDMRs in SINE repeats (P < 10(-100)) was also identified. Integration of DNAm and gene expression data showed that the expression pattern of genes associated with CGI shore cDMRs was able to discriminate between disease phenotypes. This study establishes MeDIP-seq as an effective method to analyze cancer methylomes.


Subject(s)
DNA Methylation/genetics , Epigenomics , Nerve Sheath Neoplasms/genetics , Cluster Analysis , CpG Islands/genetics , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , Minisatellite Repeats/genetics , Oligonucleotide Array Sequence Analysis/methods
16.
Stem Cells ; 31(1): 190-202, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23132836

ABSTRACT

Polycomb group proteins are essential regulators of stem cell function during embryonic development and in adult tissue homeostasis. Bmi1, a key component of the Polycomb Repressive Complex 1, is highly expressed in undifferentiated neural stem cells (NSC) as well as in several human cancers including high-grade gliomas--highly aggressive brain tumors. Using a conditional gene activation approach in mice, we show that overexpression of Bmi1 induces repressive epigenetic regulation of the promoter of Survivin, a well-characterized antiapoptotic protein. This phenomenon is cell type-specific and it leads to apoptotic death of progenitor cells exclusively upon commitment toward a neuronal fate. Moreover, we show that this is triggered by increased oxidative stress-induced DNA damage. In contrast, undifferentiated NSC as well as glioma-initiating cells display an open chromatin configuration at the Survivin promoter and do not undergo apoptotic death. These findings raise the possibility that normal and neoplastic stem cells depend on the same mechanism for surviving the hyperproliferative state induced by increased Bmi1 expression.


Subject(s)
Glioma/metabolism , Inhibitor of Apoptosis Proteins/metabolism , Neural Stem Cells/physiology , Polycomb Repressive Complex 1/metabolism , Proto-Oncogene Proteins/metabolism , Repressor Proteins/metabolism , Animals , Brain Neoplasms/metabolism , Cell Differentiation , Cell Proliferation , Cerebral Cortex/cytology , Chromatin/metabolism , DNA Damage , DNA Methylation , Epigenesis, Genetic , Gene Expression Profiling , Glioma/genetics , Inhibitor of Apoptosis Proteins/genetics , Jumonji Domain-Containing Histone Demethylases/metabolism , Mice , Neurogenesis , Oxidative Stress , Promoter Regions, Genetic , Repressor Proteins/genetics , Survivin , Ubiquitination
17.
BMC Cancer ; 14: 182, 2014 Mar 14.
Article in English | MEDLINE | ID: mdl-24628919

ABSTRACT

BACKGROUND: MLK3 gene mutations were described to occur in about 20% of microsatellite unstable gastrointestinal cancers and to harbor oncogenic activity. In particular, mutation P252H, located in the kinase domain, was found to have a strong transforming potential, and to promote the growth of highly invasive tumors when subcutaneously injected in nude mice. Nevertheless, the molecular mechanism underlying the oncogenic activity of P252H mutant remained elusive. METHODS: In this work, we performed Illumina Whole Genome arrays on three biological replicas of human HEK293 cells stably transfected with the wild-type MLK3, the P252H mutation and with the empty vector (Mock) in order to identify the putative signaling pathways associated with P252H mutation. RESULTS: Our microarray results showed that mutant MLK3 deregulates several important colorectal cancer- associated signaling pathways such as WNT, MAPK, NOTCH, TGF-beta and p53, helping to narrow down the number of potential MLK3 targets responsible for its oncogenic effects. A more detailed analysis of the alterations affecting the WNT signaling pathway revealed a down-regulation of molecules involved in the canonical pathway, such as DVL2, LEF1, CCND1 and c-Myc, and an up-regulation of DKK, a well-known negative regulator of canonical WNT signaling, in MLK3 mutant cells. Additionally, FZD6 and FZD10 genes, known to act as negative regulators of the canonical WNT signaling cascade and as positive regulators of the planar cell polarity (PCP) pathway, a non-canonic WNT pathway, were found to be up-regulated in P252H cells. CONCLUSION: The results provide an overall view of the expression profile associated with mutant MLK3, and they support the functional role of mutant MLK3 by showing a deregulation of several signaling pathways known to play important roles in the development and progression of colorectal cancer. The results also suggest that mutant MLK3 may be a novel modulator of WNT signaling, and pinpoint the activation of PCP pathway as a possible mechanism underlying the invasive potential of MLK3 mutant cells.


Subject(s)
Colorectal Neoplasms/genetics , MAP Kinase Kinase Kinases/genetics , Signal Transduction/genetics , Cell Line, Tumor , Colorectal Neoplasms/metabolism , Genome-Wide Association Study , HEK293 Cells , Humans , MAP Kinase Kinase Kinases/biosynthesis , Mutagenesis, Site-Directed , Mitogen-Activated Protein Kinase Kinase Kinase 11
18.
Brain ; 136(Pt 10): 3096-105, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24022475

ABSTRACT

We describe a previously unreported syndrome characterized by secondary (post-natal) microcephaly with fronto-temporal lobe hypoplasia, multiple pituitary hormone deficiency, seizures, severe visual impairment and abnormalities of the kidneys and urinary tract in a highly consanguineous family with six affected children. Homozygosity mapping and exome sequencing revealed a novel homozygous frameshift mutation in the basic helix-loop-helix transcription factor gene ARNT2 (c.1373_1374dupTC) in affected individuals. This mutation results in absence of detectable levels of ARNT2 transcript and protein from patient fibroblasts compared with controls, consistent with nonsense-mediated decay of the mutant transcript and loss of ARNT2 function. We also show expression of ARNT2 within the central nervous system, including the hypothalamus, as well as the renal tract during human embryonic development. The progressive neurological abnormalities, congenital hypopituitarism and post-retinal visual pathway dysfunction in affected individuals demonstrates for the first time the essential role of ARNT2 in the development of the hypothalamo-pituitary axis, post-natal brain growth, and visual and renal function in humans.


Subject(s)
Aryl Hydrocarbon Receptor Nuclear Translocator/genetics , Basic Helix-Loop-Helix Transcription Factors/genetics , Hypopituitarism/genetics , Kidney/abnormalities , Microcephaly/genetics , Mutation/genetics , Pituitary Hormones/metabolism , Visual Perception , Child , Child, Preschool , Female , Humans , Hypopituitarism/diagnosis , Hypothalamus/metabolism , Kidney/metabolism , Male , Microcephaly/diagnosis , Pituitary Hormones/genetics , Syndrome , Transcription Factors
19.
J Neuroinflammation ; 10: 29, 2013 Feb 21.
Article in English | MEDLINE | ID: mdl-23432807

ABSTRACT

Autoinflammatory diseases are rare illnesses characterized by apparently unprovoked inflammation without high-titer auto-antibodies or antigen-specific T cells. They may cause neurological manifestations, such as meningitis and hearing loss, but they are also characterized by non-neurological manifestations. In this work we studied a 30-year-old man who had a chronic disease characterized by meningitis, progressive hearing loss, persistently raised inflammatory markers and diffuse leukoencephalopathy on brain MRI. He also suffered from chronic recurrent osteomyelitis of the mandible. The hypothesis of an autoinflammatory disease prompted us to test for the presence of mutations in interleukin-1-pathway genes and to investigate the function of this pathway in the mononuclear cells obtained from the patient. Search for mutations in genes associated with interleukin-1-pathway demonstrated a novel NLRP3 (CIAS1) mutation (p.I288M) and a previously described MEFV mutation (p.R761H), but their combination was found to be non-pathogenic. On the other hand, we uncovered a selective interleukin-6 hypersecretion within the central nervous system as the likely pathogenic mechanism. This is also supported by the response to the anti-interleukin-6-receptor monoclonal antibody tocilizumab, but not to the recombinant interleukin-1-receptor antagonist anakinra. Exome sequencing failed to identify mutations in other genes known to be involved in autoinflammatory diseases. We propose that the disease described in this patient might be a prototype of a novel category of autoinflammatory diseases characterized by prominent neurological involvement.


Subject(s)
Interleukin-6/metabolism , Meningitis/diagnosis , Meningitis/metabolism , Nervous System Diseases/diagnosis , Nervous System Diseases/metabolism , Adult , Cells, Cultured , Chronic Disease , Hereditary Autoinflammatory Diseases/diagnosis , Hereditary Autoinflammatory Diseases/genetics , Hereditary Autoinflammatory Diseases/metabolism , Humans , Male , Meningitis/genetics , Monocytes/metabolism , Nervous System Diseases/genetics , Young Adult
20.
Nucleic Acids Res ; 39(Database issue): D849-55, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20929875

ABSTRACT

The International Knockout Mouse Consortium (IKMC) aims to mutate all protein-coding genes in the mouse using a combination of gene targeting and gene trapping in mouse embryonic stem (ES) cells and to make the generated resources readily available to the research community. The IKMC database and web portal (www.knockoutmouse.org) serves as the central public web site for IKMC data and facilitates the coordination and prioritization of work within the consortium. Researchers can access up-to-date information on IKMC knockout vectors, ES cells and mice for specific genes, and follow links to the respective repositories from which corresponding IKMC products can be ordered. Researchers can also use the web site to nominate genes for targeting, or to indicate that targeting of a gene should receive high priority. The IKMC database provides data to, and features extensive interconnections with, other community databases.


Subject(s)
Databases, Genetic , Mice, Knockout , Alleles , Animals , Gene Targeting , Genetic Vectors , Genomics , Internet , Mice , Molecular Sequence Annotation , User-Computer Interface
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