RESUMO
BACKGROUND: Although recent studies have greatly advanced understanding of deep molluscan phylogeny, placement of some taxa remains uncertain as different datasets support competing class-relationships. Traditionally, morphologists have placed Monoplacophora, a group of morphologically simple, limpet-like molluscs as sister group to all other conchiferans (shelled molluscs other than Polyplacophora), a grouping that is supported by the latest large-scale phylogenomic study that includes Laevipilina. However, molecular datasets dominated by nuclear ribosomal genes support Monoplacophora + Polyplacophora (Serialia). Here, we evaluate the potential of mitochondrial genome data for resolving placement of Monoplacophora. RESULTS: Two complete (Laevipilina antarctica and Vema ewingi) and one partial (Laevipilina hyalina) mitochondrial genomes were sequenced, assembled, and compared. All three genomes show a highly similar architecture including an unusually high number of non-coding regions. Comparison of monoplacophoran gene order shows a gene arrangement pattern not previously reported; there is an inversion of one large gene cluster. Our reanalyses of recently published polyplacophoran mitogenomes show, however, that this feature is also present in some chiton species. Maximum Likelihood and Bayesian Inference analyses of 13 mitochondrial protein-coding genes failed to robustly place Monoplacophora and hypothesis testing could not reject any of the evaluated placements of Monoplacophora. CONCLUSIONS: Under both serialian or aculiferan-conchiferan scenarios, the observed gene cluster inversion appears to be a convergent evolution of gene arrangements in molluscs. Our phylogenetic results are inconclusive and sensitive to taxon sampling. Aculifera (Polyplacophora + Aplacophora) and Conchifera were never recovered. However, some analyses recovered Serialia (Monoplacophora + Polyplacophora), Diasoma (Bivalvia + Scaphopoda) or Pleistomollusca (Bivalvia + Gastropoda). Although we could not shed light on deep evolutionary traits of Mollusca we found unique patterns of gene arrangements that are common to monoplacophoran and chitonine polyplacophoran species but not to acanthochitonine Polyplacophora. Complete mitochondrial genome of Laevipilina antarctica.
Assuntos
Ordem dos Genes , Genoma Mitocondrial , Moluscos/genética , Animais , Teorema de Bayes , Evolução Biológica , Bivalves/genética , Gastrópodes/genética , Família Multigênica , FilogeniaAssuntos
Transtornos Globais do Desenvolvimento Infantil/genética , Mutação/genética , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Sequência de Bases , Criança , Feminino , Frequência do Gene , Estudo de Associação Genômica Ampla , Genótipo , Alemanha , Haplótipos/genética , Humanos , Masculino , Dados de Sequência Molecular , Proteína Ribossômica L10 , Análise de Sequência de DNARESUMO
Gastrointestinal stromal tumours (GISTs) with deletions in KIT exon 11 are characterized by higher proliferation rates and shorter disease-free survival times, compared to GISTs with KIT exon 11 point mutations. Up-regulation of cyclin D is a crucial event for entry into the G1 phase of the cell cycle, and links mitogenic signalling to cell proliferation. Signalling from activated KIT to cyclin D is directed through the RAS/RAF/ERK, PI3K/AKT/mTOR/EIF4E, and JAK/STATs cascades. ERK and STATs initiate mRNA transcription of cyclin D, whereas EIF4E activation leads to increased translation efficiency and reduced degradation of cyclin D protein. The aim of the current study was to analyse the mRNA and protein expression as well as protein phosphorylation of central hubs of these signalling cascades in primary GISTs, to evaluate whether tumours with KIT exon 11 deletions and point mutations differently utilize these pathways. GISTs with KIT exon 11 deletions had significantly higher mitotic counts, higher proliferation rates, and shorter disease-free survival times. In line with this, they had significantly higher expression of cyclin D on the mRNA and protein level. Furthermore, there was a significantly higher amount of phosphorylated ERK1/2, and a higher protein amount of STAT3, mTOR, and EIF4E. PI3K and phosphorylated AKT were also up-regulated, but this was not significant. Ultimately, GISTs with KIT exon 11 deletions had significantly higher phosphorylation of the central negative cell-cycle regulator RB. Phosphorylation of RB is accomplished by activated cyclin D/CDK4/6 complex, and marks a central event in the release of the cell cycle. Altogether, these observations suggest increased KIT signalling with up-regulation of cyclin D as the basis for the unfavourable clinical course in GISTs with KIT exon 11 deletions.
Assuntos
Ciclinas/genética , Tumores do Estroma Gastrointestinal/genética , Proteínas Proto-Oncogênicas c-kit/genética , Regulação para Cima , Idoso , Idoso de 80 Anos ou mais , Proliferação de Células , Ciclina D , Ciclinas/metabolismo , Intervalo Livre de Doença , Éxons , Feminino , Tumores do Estroma Gastrointestinal/mortalidade , Tumores do Estroma Gastrointestinal/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Análise Serial de Proteínas , Proteínas Proto-Oncogênicas c-kit/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Deleção de Sequência , Transdução de Sinais/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologiaRESUMO
Loss of chromosome 9p is a reliable predictor of malignant behaviour in gastrointestinal stromal tumours (GISTs). p16INK4A located at 9p21 inhibits the CDK4/6/cyclin D complex from phosphorylating RB. Phosphorylation of RB through CDK4/6/cyclin D in early G(1) phase frees the transcription factor E2F1 from RB and enables mRNA transcription of genes essential for G(1)/S phase transition. This study aims to determine the impact of 9p loss on mRNA and protein expression of p16INK4A and further key cell cycle regulators in the different phases of the cell cycle. Sixty primary GISTs previously characterized for 9p loss by comparative genomic hybridization were analysed for mRNA expression of p16INK4A, p15INK4B, CDK4, CDK6, cyclin D, p21CIP1p27KIP1, CDK2, cyclin E, cyclin B, RB and E2F1, using quantitative RT-PCR. The protein expression of CDK6, CDK2, p21CIP1, p27KIP1 and phosphorylated RB (S807/S811) was evaluated using protein arrays as a novel and highly sensitive platform for profiling of protein abundance and protein phosphorylation. In parallel, the nuclear percentages of immunohistochemical staining for p16INK4A, cyclin D, E2F1 and RB were quantified on a tissue microarray. GISTs with 9p loss had significantly higher proliferation rates, higher metastatic behaviour and shorter disease-free survival. On the molecular level, GISTs with 9p loss had a significantly reduced mRNA as well as nuclear protein expression of p16INK4A. RB was significantly more phosphorylated in these tumours, together with increased mRNA expression and nuclear staining for E2F1. Furthermore, GISTs with 9p loss had up-regulation of the late G1/S phase promoters CDK2 and cyclin E. We conclude that loss of 9p accompanied by early G1 phase inhibitor p16(INK4A) down-regulation in GISTs facilitates phosphorylation of RB, enabling E2F1-dependent transcription of genes essential for late G1/S phase transition. This study provides a possible basis for the accelerated proliferation and particularly malignant behaviour in GISTs with 9p loss.
Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/genética , Tumores do Estroma Gastrointestinal/genética , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Proteínas de Ciclo Celular/genética , Inibidor p16 de Quinase Dependente de Ciclina/análise , Progressão da Doença , Fator de Transcrição E2F1/análise , Fator de Transcrição E2F1/metabolismo , Expressão Gênica , Perfilação da Expressão Gênica , Genes do Retinoblastoma , Humanos , Imuno-Histoquímica , Análise de Sequência com Séries de Oligonucleotídeos , Modelos de Riscos Proporcionais , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodosRESUMO
Deleted in Malignant Brain Tumours 1 (DMBT1) is a secreted scavenger receptor cysteine-rich protein that binds and aggregates various bacteria and viruses in vitro. Studies in adults have shown that DMBT1 is expressed mainly by mucosal epithelia and glands, in particular within the respiratory tract, and plays a role in innate immune defence. We hypothesized that respiratory DMBT1 levels may be influenced by various developmental and clinical factors such as maturity, age and bacterial infection. DMBT1 levels were studied in 205 tracheal aspirate samples of 82 ventilated preterm and full-term infants by enzyme-linked immunosorbent assay. Possible effects of various clinical parameters were tested by multiple regression analysis. DMBT1 levels increased significantly with lung maturity (P < 0.0001 for both gestational and postnatal age) and in small-for-gestational-age infants (P = 0.0179). An increase of respiratory DMBT1 levels was detected in neonatal infections (P < 0.0001). These results were supported by Western blotting. Immunohistochemical analyses of archived newborn lung sections (n = 17) demonstrated high concentrations of DMBT1 in lungs of neonates with bacterial infections. Our data show that preterm infants are able to up-regulate DMBT1 in infection as an unspecific immune reaction.
Assuntos
Doenças Transmissíveis/metabolismo , Pulmão/metabolismo , Receptores de Superfície Celular/metabolismo , Infecções Respiratórias/metabolismo , Biomarcadores/análise , Western Blotting/métodos , Proteínas de Ligação ao Cálcio , Doenças Transmissíveis/tratamento farmacológico , Doenças Transmissíveis/imunologia , Proteínas de Ligação a DNA , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Desenvolvimento Fetal/fisiologia , Idade Gestacional , Glucocorticoides/uso terapêutico , Humanos , Imuno-Histoquímica , Indometacina/uso terapêutico , Recém-Nascido , Recém-Nascido Prematuro , Recém-Nascido Pequeno para a Idade Gestacional , Pulmão/embriologia , Pulmão/imunologia , Masculino , Análise Multivariada , Gravidez , Receptores de Superfície Celular/análise , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/imunologia , Proteínas Supressoras de TumorRESUMO
OBJECTIVE: Mesenchymal stem cells (MSCs) are a population of cells broadly discussed to support cartilage repair. The differentiation of MSCs into articular chondrocytes is, however, still poorly understood on the molecular level. The aim of this study was to perform an almost genome-wide screen for genes differentially expressed between cartilage and MSCs and to extract new markers useful to define chondrocyte differentiation stages. METHODS: Gene expression profiles of MSCs (n=8) and articular cartilage from OA patients (n=7) were compared on a 30,000 cDNA-fragment array and differentially expressed genes were extracted by subtraction. Expression of selected genes was assessed during in vitro chondrogenic differentiation of MSCs and during dedifferentiation of expanded chondrocytes using quantitative and semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Protein secretion was measured by enzyme-linked immunosorbent assay. RESULTS: Eighty-seven genes were differentially expressed between MSCs and cartilage with a more than three-fold difference. Sixty-seven of them were higher expressed in cartilage and among them 15 genes were previously not detected in cartilage. Differential expression was confirmed for 69% of 26 reanalysed genes by RT-PCR. The profiles of three unknown transcripts and six protease-related molecules were characterised during differentiation. SERPINA1 and SERPINA3 mRNA expression correlated with chondrogenic differentiation of MSCs and dedifferentiation of chondrocytes, and SERPINA1 protein levels in culture supernatants could be correlated alike. CONCLUSIONS: cDNA-array analysis identified SERPINA1 and A3 as new differentiation-relevant genes for cartilage. Since SERPINA1 secretion correlated with both chondrogenesis of MSCs and dedifferentiation during chondrocyte expansion, it represents an attractive marker for refinement of chondrocyte differentiation.
Assuntos
Cartilagem Articular/citologia , Condrócitos/citologia , Condrogênese , Perfilação da Expressão Gênica , Células-Tronco Mesenquimais/citologia , Osteoartrite/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos de Diferenciação/genética , Cartilagem Articular/metabolismo , Diferenciação Celular , Condrócitos/metabolismo , Ensaio de Imunoadsorção Enzimática , Humanos , Células-Tronco Mesenquimais/metabolismo , Análise em Microsséries , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Osteoartrite/metabolismo , Osteoartrite/patologia , RNA Mensageiro/análise , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serpinas/genética , Serpinas/metabolismo , alfa 1-Antitripsina/genética , alfa 1-Antitripsina/metabolismoRESUMO
Vacuole membrane protein 1 (Vmp1) is described as a cancer-relevant cell cycle modulator, but the function of this protein and its mode of action in tumor progression are still unknown. In this study, we show that the VMP1 mRNA level is significantly reduced in kidney cancer metastases as compared to primary tumors. Further, VMP1 expression is also decreased in the invasive breast cancer cell lines HCC1954 and MDA-MB-231 as compared to the non-invasive cell lines MCF-12A, T-47D and MCF-7. We show for the first time that Vmp1 is a plasma membrane protein and an essential component of initial cell-cell contacts and tight junction formation. It interacts with the tight junction protein Zonula Occludens-1 and colocalizes in spots between neighboring HEK293 cells. Downregulation of VMP1 by RNAi results in loss of cell adherence, and increases the invasion capacity of the non-invasive kidney cancer cell line Caki-2. In conclusion, our findings establish Vmp1 to be a novel cell-cell adhesion protein and that its expression level determines the invasion and metastatic potential of cancer cells.
Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Neoplasias Renais/patologia , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Vacúolos/química , Animais , Neoplasias da Mama/química , Neoplasias da Mama/genética , Células COS , Carcinoma Ductal de Mama/química , Carcinoma Ductal de Mama/genética , Adesão Celular/genética , Comunicação Celular/genética , Linhagem Celular , Linhagem Celular Tumoral , Chlorocebus aethiops , Feminino , Humanos , Neoplasias Renais/química , Neoplasias Renais/genética , Proteínas de Membrana/biossíntese , Invasividade Neoplásica , Junções Íntimas/química , Junções Íntimas/metabolismo , Junções Íntimas/patologia , Células Tumorais Cultivadas , Vacúolos/patologiaRESUMO
The matter of concern are algorithms for the discrimination of direct from indirect regulatory effects from an interaction graph built up by error-prone measurements. Many of these algorithms can be cast as a rule for the removal of a single edge of the graph, such that the remaining graph is still consistent with the data. A set of mild conditions is given under which iterated application of such a rule leads to a unique minimal consistent graph. We show that three of the common methods for direct interactions search fulfill these conditions, thus providing a justification of their use. The main issues a reconstruction algorithm has to deal with, are the noise in the data, the presence of regulatory cycles, and the direction of the regulatory effects. We introduce a novel rule that, in contrast to the previously mentioned methods, simultaneously takes into account all these aspects. An efficient algorithm for the computation of the minimal graph is given, whose time complexity is cubic in the number of vertices of the graph. Finally, we demonstrate the utility of our method in a simulation study.
Assuntos
Redes Reguladoras de Genes , Algoritmos , Gráficos por Computador , Simulação por ComputadorAssuntos
Biomarcadores Tumorais/genética , Pesquisa em Genética , Neoplasias da Próstata/genética , Análise Mutacional de DNA , DNA de Neoplasias/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Hibridização in Situ Fluorescente , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , Próstata/patologia , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/patologia , Proteômica , RNA Neoplásico/genética , Análise de SobrevidaRESUMO
Autism has a strong genetic background with a higher frequency of affected males suggesting involvement of X-linked genes and possibly also other factors causing the unbalanced sex ratio in the etiology of the disorder. We have identified two missense mutations in the ribosomal protein gene RPL10 located in Xq28 in two independent families with autism. We have obtained evidence that the amino-acid substitutions L206M and H213Q at the C-terminal end of RPL10 confer hypomorphism with respect to the regulation of the translation process while keeping the basic translation functions intact. This suggests the contribution of a novel, possibly modulating aberrant cellular function operative in autism. Previously, we detected high expression of RPL10 by RNA in situ hybridization in mouse hippocampus, a constituent of the brain limbic system known to be afflicted in autism. Based on these findings, we present a model for autistic disorder where a change in translational function is suggested to impact on those cognitive functions that are mediated through the limbic system.
Assuntos
Transtorno Autístico/genética , Transtorno Autístico/metabolismo , Deficiência Intelectual Ligada ao Cromossomo X/genética , Mutação de Sentido Incorreto , Biossíntese de Proteínas/genética , Proteínas Ribossômicas/genética , Substituição de Aminoácidos , Animais , Transtorno Autístico/patologia , Cromossomos Humanos X , Feminino , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Masculino , Deficiência Intelectual Ligada ao Cromossomo X/metabolismo , Camundongos , Modelos Neurológicos , Linhagem , Proteína Ribossômica L10 , Proteínas Ribossômicas/metabolismoRESUMO
BACKGROUND AND AIMS: Perturbation of differentiation of the crypt-villus axis of the human small intestine is associated with several intestinal disorders of clinical importance. At present, differentiation of small intestinal enterocytes in the crypt-villus axis is not well characterised. SUBJECTS AND METHODS: Expression profiling of microdissected enterocytes lining the upper part of crypts or the middle of villi was performed using the Affymetrix X3P arrays and several methods for confirmation. RESULTS: A total of 978 differentially expressed sequences representing 778 unique UniGene IDs were found and categorised into four functional groups. In enterocytes lining the upper part of crypts, cell cycle promoting genes and transcription/translation related genes were predominantly expressed, whereas in enterocytes lining the middle of villi, high expression of cell cycle inhibiting genes, metabolism related genes, and vesicle/transport related genes was found. CONCLUSION: Two types of enterocytes were dissected at the molecular level, the non-absorptive enterocyte located in the upper part of crypts and the absorptive enterocyte found in the middle of villi. These data improve our knowledge about the physiology of the crypt-villus architecture in human small intestine and provide new insights into pathophysiological phenomena, such as villus atrophy, which is clinically important.
Assuntos
Enterócitos/citologia , Absorção Intestinal/genética , Intestino Delgado/citologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Diferenciação Celular/genética , Enterócitos/metabolismo , Feminino , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Genes cdc , Humanos , Absorção Intestinal/fisiologia , Intestino Delgado/metabolismo , Masculino , Microdissecção/métodos , Pessoa de Meia-Idade , Biossíntese de Proteínas , Transcrição Gênica/genéticaRESUMO
Within the framework of the large interdisciplinary projects in biology, in particular the human genome project, a variety of novel technologies with unprecedented value for the analysis of clinical issues have been developed. DNA microarrays are a prominent example of this: they are powerful tools to investigate global gene expression in tumors and their corresponding normal tissues, to classify tumors based on their molecular properties, and to identify novel targets for future tumor therapy. Here, we review recent results of global gene expression analyses in renal cell carcinoma and discuss their implications for the diagnosis, prognosis, and therapy of human cancer.
Assuntos
Carcinoma de Células Renais/genética , Marcadores Genéticos/genética , Neoplasias Renais/genética , Análise de Sequência com Séries de Oligonucleotídeos , Carcinoma de Células Renais/diagnóstico , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/terapia , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Neoplasias Renais/diagnóstico , Neoplasias Renais/mortalidade , Neoplasias Renais/terapia , Prognóstico , Taxa de SobrevidaRESUMO
BACKGROUND: We studied the expression of DMBT1 (deleted in malignant brain tumor 1), a putative tumor suppressor gene, in normal, proliferative, and malignant breast epithelium and its possible relation to cell cycle. METHODS: Sections from 17 benign lesions and 55 carcinomas were immunostained with anti DMBT1 antibody (DMBTh12) and sections from 36 samples, were double-stained also with anti MCM5, one of the 6 pre-replicative complex proteins with cell proliferation-licensing functions. DMBT1 gene expression at mRNA level was assessed by RT-PCR in frozen tissues samples from 39 patients. RESULTS: Normal glands and hyperplastic epithelium in benign lesions displayed a luminal polarized DMBTh12 immunoreactivity. Normal and hyperplastic epithelium adjacent to carcinomas showed a loss of polarization, with immunostaining present in basal and perinuclear cytoplasmic compartments. DMBT1 protein expression was down-regulated in the cancerous lesions compared to the normal and/or hyperplastic epithelium adjacent to carcinomas (3/55 positive carcinomas versus 33/42 positive normal/hyperplastic epithelia; p = 0.0001). In 72% of cases RT-PCR confirmed immunohistochemical results. Most of normal and hyperplastic mammary cells positive with DMBTh12 were also MCM5-positive. CONCLUSIONS: The redistribution and up-regulation of DMBT1 in normal and hyperplastic tissues flanking malignant tumours and its down-regulation in carcinomas suggests a potential role in breast cancer. Moreover, the concomitant expression of DMTB1 and MCM5 suggests its possible association with the cell-cycle regulation.
Assuntos
Aglutininas/metabolismo , Neoplasias da Mama/genética , Carcinoma/genética , Receptores de Superfície Celular/metabolismo , Mama/patologia , Neoplasias da Mama/patologia , Proteínas de Ligação ao Cálcio , Carcinoma/patologia , Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Citoplasma/metabolismo , Citoplasma/patologia , Proteínas de Ligação a DNA , Regulação para Baixo , Epitélio/patologia , Humanos , Hiperplasia/genética , Hiperplasia/patologia , Imuno-Histoquímica , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Supressoras de TumorRESUMO
Salivary agglutinin (SAG) is encoded by the gene Deleted in Malignant Brain Tumors 1 (DMBT1) and represents the salivary variant of DMBT1 (DMBT1(SAG)). While SAG is a bona fide anti-caries factor, DMBT1 was proposed as a candidate tumor-suppressor for brain, digestive tract, and lung cancer. Though DMBT1(SAG) is expressed in the salivary glands, its expression in salivary gland tumors is unknown. Here we analyzed DMBT1(SAG) expression in 20 salivary gland tumors and 14 tumor-flanking tissues by immunohistochemistry. DMBT1(SAG) in salivary gland tumors resembles the changes of expression levels known from DMBT1 in tumors in other cancer types. Particularly, DMBT1(SAG) was up-regulated in 10/14 tumor-flanking tissues, and a strong staining of the luminal content in the tumor and/or the tumor-flanking tissue was observed in 14/20 cases. This suggests that, in addition to its role in caries defense, SAG may serve as a potential tumor indicator and/or tumor suppressor in salivary gland tissue.
Assuntos
Aglutininas/metabolismo , Carcinoma/genética , Receptores de Superfície Celular/metabolismo , Neoplasias das Glândulas Salivares/genética , Glândulas Salivares/metabolismo , Proteínas e Peptídeos Salivares/metabolismo , Aglutininas/genética , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Biópsia , Proteínas de Ligação ao Cálcio , Carcinoma/metabolismo , Carcinoma/patologia , Proteínas de Ligação a DNA , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Receptores de Superfície Celular/genética , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Neoplasias das Glândulas Salivares/metabolismo , Neoplasias das Glândulas Salivares/patologia , Proteínas e Peptídeos Salivares/genética , Proteínas Supressoras de Tumor , Regulação para CimaRESUMO
The results from several genome scans indicate that chromosome 2q21-q33 is likely to contain an autism susceptibility locus. We studied the potential contribution of nine positional and functional candidate genes: TBR-1; GAD1; DLX1; DLX2; cAMP-GEFII; CHN1; ATF2; HOXD1 and NEUROD1. Screening these genes for DNA variants and association analysis using intragenic single nucleotide polymorphisms did not provide evidence for a major role in the aetiology of autism. Four rare nonsynonymous variants were identified, however, in the cAMP-GEFII gene. These variants were present in five families, where they segregate with the autistic phenotype, and were not observed in control individuals. The significance of these variants is unclear, as their low frequency in IMGSAC families does not account for the relatively strong linkage signal at the 2q locus. Further studies are needed to clarify the contribution of cAMP-GEFII gene variants to autism susceptibility.
Assuntos
Transtorno Autístico/genética , Proteínas de Transporte/genética , Cromossomos Humanos Par 2 , AMP Cíclico/metabolismo , Fatores de Troca do Nucleotídeo Guanina/genética , Animais , Proteínas de Transporte/metabolismo , Feminino , Predisposição Genética para Doença , Testes Genéticos , Variação Genética , Genótipo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Desequilíbrio de Ligação , Masculino , Camundongos , Mutação de Sentido Incorreto , Linhagem , Polimorfismo de Nucleotídeo ÚnicoRESUMO
AIMS: To investigate the participation of DMBT-1, a candidate tumour suppressor gene, in the development of intrahepatic cholangiocarcinoma via intraductal papillary neoplasm of the liver (IPN-L) arising in hepatolithiasis. DMBT-1 plays a role in mucosal immune defence. METHODS AND RESULTS: The expression of DMBT-1 was examined immunohistochemically in biliary epithelial cells in hepatolithiasis (n = 25), invasive and non-invasive cholangiocarcinoma associated with hepatolithiasis (n = 52), IPN-L with hepatolithiasis (n = 49), cholangiocarcinoma without hepatolithiasis (n = 32), and 10 normal control livers. DMBT-1 was expressed more frequently in the biliary epithelia of hepatolithiasis when compared with normal livers (P < 0.05). DMBT-1 expression was also frequent in IPN-L (57%) and non-invasive cholangiocarcinoma (79%). By contrast, DMBT-1 was decreased in invasive cholangiocarcinoma with and without hepatolithiasis (50% and 30%, respectively) (P < 0.05). The homozygous deletion of the DMBT-1 gene was recognized in four (20%) of 20 cholangiocarcinoma tissues and two (50%) of four cholangiocarcinoma cell lines, corresponding to the reduction of DMBT-1 expression. No deletion was detected in hepatolithiasis tissues. CONCLUSION: DMBT-1 expression is increased in IPN-L and non-invasive cholangiocarcinoma as well as in biliary epithelia in hepatolithiasis. Decreased expression of DMBT-1 and homozygous deletion of the DMBT-1 gene in invasive cholangiocarcinoma suggest that they occur in the late stage of cholangiocarcinogenesis.
Assuntos
Aglutininas , Neoplasias dos Ductos Biliares/genética , Neoplasias Encefálicas/genética , Colangiocarcinoma/genética , Deleção de Genes , Regulação Neoplásica da Expressão Gênica/genética , Receptores de Superfície Celular/genética , Neoplasias dos Ductos Biliares/metabolismo , Neoplasias dos Ductos Biliares/patologia , Ductos Biliares Intra-Hepáticos/patologia , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Proteínas de Ligação ao Cálcio , Carcinoma Papilar/genética , Carcinoma Papilar/metabolismo , Carcinoma Papilar/patologia , Linhagem Celular Tumoral , Colangiocarcinoma/metabolismo , Colangiocarcinoma/patologia , Proteínas de Ligação a DNA , Humanos , Técnicas Imunoenzimáticas , Hibridização In Situ , Litíase/patologia , RNA Mensageiro/metabolismo , RNA Neoplásico/análise , Receptores de Superfície Celular/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Supressoras de TumorRESUMO
Genetic studies indicate that chromosome 7q is likely to contain an autism susceptibility locus (AUTS1). We have followed a positional candidate gene approach to identify relevant gene(s) and report here the analysis of reelin (RELN), a gene located under our peak of linkage. Screening RELN for DNA changes identified novel missense variants absent in a large control group; however, the low frequency of these mutations does not explain the relatively strong linkage results on 7q. Furthermore, analysis of a previously reported triplet repeat polymorphism and intragenic single nucleotide polymorphisms, using the transmission disequilibrium test, provided no evidence for association with autism in IMGSAC and German singleton families. The analysis of RELN suggests that it probably does not play a major role in autism aetiology, although further analysis of several missense mutations is warranted in additional affected individuals.
Assuntos
Transtorno Autístico/genética , Moléculas de Adesão Celular Neuronais/genética , Proteínas da Matriz Extracelular/genética , Desequilíbrio de Ligação , Éxons/genética , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Proteínas do Tecido Nervoso , Polimorfismo de Nucleotídeo Único , Proteína Reelina , Serina EndopeptidasesRESUMO
Runt-homologous molecules are characterized by their DNA binding runt-domain which is highly conserved within bilaterians. The three mammalian runt-genes are master regulators in cartilage/bone formation and hematopoiesis. Historically these features evolved in Craniota and might have been promoted by runt-gene duplication events. The purpose of this study was therefore to investigate how many runt-genes exist in the stem species of chordates, by analyzing the number of runt-genes in what is likely to be the closest living relative of Craniota-amphioxus. To acquire further insight into the possible role of runt-genes in early chordate evolution we have determined the number of runt-genes in sea urchins and have analyzed the runt-expression pattern in this species. Our findings demonstrate the presence of a single runt-gene in amphioxus and sea urchin, which makes it highly likely that the stem species of chordates harbored only a single runt-gene. This suggests that runt-gene duplications occurred later in chordate phylogeny, and are possibly also associated with the evolution of features such as hematopoiesis, cartilage and bone development. In sea urchin embryos runt-expression involves cells of endodermal, mesodermal and ectodermal origin. This complex pattern of expression might reflect the multiple roles played by runt-genes in mammals. A strong runt-signal in the gastrointestinal tract of the sea urchin is in line with runt-expression in the intestine of nematodes and in the murine gastrointestinal tract, and seems to be one of the phylogenetically ancient runt-expression domains.
Assuntos
Cordados não Vertebrados/genética , Evolução Molecular , Duplicação Gênica , Proteínas de Neoplasias , Ouriços-do-Mar/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Animais , Southern Blotting , Expressão Gênica , Humanos , Hibridização In Situ , Dados de Sequência Molecular , Filogenia , Homologia de Sequência de AminoácidosRESUMO
Deleted in malignant brain tumours 1 (DMBT1), a candidate tumour suppressor gene located on chromosome 10q25.3-q26.1, has recently been identified and found to be deleted in several different types of human tumours. In melanomas, the chromosomal region 10q22-qter is commonly affected by losses, hence we screened primary melanoma samples for losses of heterozygosity (LOH), and acquired melanocytic naevi and melanomas for transcription of DMBT1 and protein expression. Of 38 informative melanomas, 1 nodular melanoma and 2 subcutaneous metastases showed LOH of both microsatellites flanking the gene, suggesting loss of 1 DMBT1 allele. Three further melanomas showed LOH at 1 informative locus but were heterozygous for the second marker. Applying reverse-transcription polymerase chain reaction (RT-PCR), DMBT1 transcription was not found in melanomas. However, DMBT1 transcription was also absent from the majority of naevi from which melanomas frequently arise, making down-regulation of gene transcription during transformation from naevus to melanoma unlikely. Immunohistochemistry showed nerves, sweat glands and the stratum spinosum of the epidermis to be DMBT1 protein positive, whereas the naevi and melanoma cells themselves were negative. All considered, the candidate tumour suppressor gene DMBT1 does not appear to be a major inactivation target in the development of melanomas.