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100 Publications visible to you, out of a total of 100
PSFC: a Pathway Signal Flow Calculator App for Cytoscape.

Abstract (Expand)

Cell signaling pathways are sequences of biochemical reactions that propagate an input signal, such as a hormone binding to a cell-surface receptor, into the cell to trigger a reactive process. Assessment … of pathway activities is crucial for determining which pathways play roles in disease versus normal conditions. To date various pathway flow/perturbation assessment tools are available, however they are constrained to specific algorithms and specific data types. There are no accepted standards for evaluation of pathway activities or simulation of flow propagation events in pathways, and the results of different software are difficult to compare. Here we present Pathway Signal Flow Calculator (PSFC), a Cytoscape app for calculation of a pathway signal flow based on the pathway topology and node input data. The app provides a rich framework for customization of different signal flow algorithms to allow users to apply various approaches within a single computational framework.

Authors: L. Nersisyan, G. Johnson, M. Riel-Mehan, A. Pico, A. Arakelyan

Date Published: 25th Apr 2017

Publication Type: Journal

Characterization of BRCA1/2 mutations in patients with family history of breast cancer in Armenia.

Abstract (Expand)

Background. Breast cancer is one of the most common cancers in women worldwide. The germline mutations of the BRCA1 and BRCA2 genes are the most significant and well characterized genetic risk factors … for hereditary breast cancer. Intensive research in the last decades has demonstrated that the incidence of mutations varies widely among different populations. In this study we attempted to perform a pilot study for identification and characterization of mutations in BRCA1 and BRCA2 genes among Armenian patients with family history of breast cancer and their healthy relatives. Methods. We performed targeted exome sequencing for BRCA1 and BRCA2 genes in 6 patients and their healthy relatives. After alignment of short reads to the reference genome, germline single nucleotide variation and indel discovery was performed using GATK software. Functional implications of identified variants were assessed using ENSEMBL Variant Effect Predictor tool. Results. In total, 39 single nucleotide variations and 4 indels were identified, from which 15 SNPs and 3 indels were novel. No known pathogenic mutations were identified, but 2 SNPs causing missense amino acid mutations had significantly increased frequencies in the study group compared to the 1000 Genome populations. Conclusions. Our results demonstrate the importance of screening of BRCA1 and BRCA2 gene variants in the Armenian population in order to identity specifics of mutation spectrum and frequencies and enable accurate risk assessment of hereditary breast cancers. Keywords: BRCA1; BRCA2; breast cancer; mutation screening; targeted exome sequencing.

Authors: Sofi Atshemyan, Andranik Chavushyan, Nerses Berberian, Arthur Sahakyan, Roksana Zakharyan, Arsen Arakelyan

Date Published: 10th Jan 2017

Publication Type: Journal

Transcription Factors in Schizophrenia: A Current View of Genetic Aspects

Abstract (Expand)

Background: Schizophrenia is a polygenic mental disorder with about 80% heritability. Growing evidence indicated that synaptic dysfunctions contribute to SCZ etiopathogenesis. The context and purpose …e of the study: Transcription factors play an important role in the regulation of gene expression. Whereas expression analysis of transcription factor has been performed, studies of their genetic variants are limited. The current review article summarizes data on transcription factors early growth response 3 (EGR3), c-fos transcription (FOS), immune early response 5 (IER5), c-jun (JUN), Nk2 Homeobox 1 (NKX2-1), and transcription factor 4 (TCF4) encoding genes in schizophrenia. Results and main findings: An important role of the mentioned genes in this pathology has been identified. Conclusions: We concluded that the genetic variants of the transcription factor encodng genes might contribute to the assessment of disease susceptibility and can find potential use for the development of genetically-driven diagnostic approaches in the future.

Author: Zakharyan Roksana

Date Published: 30th Dec 2016

Publication Type: Journal

Schizophrenia-associated Risk and Protective Variants of c-Fos Encoding Gene

Abstract (Expand)

Defects in synaptic plasticity play a key role in pathophysiology of schizophrenia. Pathomechanisms responsible for synaptic plasticity alterations in schizophrenia are very complicated and not well … defined. Transcription factor c-Fos plays an important role in regulation of synaptic plasticity. In the present study we evaluated the association of rs7101 and rs1063169 single nucleotide polymorphisms (SNPs) of c-Fos encoding gene (FOS) with schizophrenia. A total of 604 DNA samples of schizophrenia-affected and healthy subjects of Armenian ancestry were genotyped using polymerase chain reaction with sequence-specific primers. Also, comparative determination of the blood levels of c-Fos protein in schizophrenia patients and controls was performed using the enzyme-linked immunosorbent assay. Potential interaction between protein level and genotypes as well as relationships between genotypes/protein level and clinical-demographic characteristics of schizophrenia patients were assessed. The results obtained demonstrated that mutant allele of FOS rs1063169 SNP is negatively associated with schizophrenia and may be nominated as a protective factor for this disorder. On the other hand, according to our results, the FOS rs7101T mutant allele is positively associated with schizophrenia and, therefore, may be considered as a risk factor for this disorder. In addition, decreased c-Fos plasma levels in schizophrenia patients compared to controls were found. In conclusion, the results of this study suggest that FOS is among the candidate genes of schizophrenia and that changes in the expression of c-Fos protein may contribute to molecular pathomechanisms of schizophrenia-related alterations in synaptic plasticity.

Authors: Anna Boyajyan, Roksana Zakharyan, Sofi Atshemyan, Andranik Chavushyan, Gohar Mkrtchyan

Date Published: 26th Jan 2016

Publication Type: Journal

No Association of the Complexin-3 Gene Polymorphism with Schizophrenia

Abstract (Expand)

Background: Schizophrenia (SCZ) is a multifactorial mental disease. Whereas complex interplay of genes and environment contributes to the SCZ, the disorder has still unclear biological background. … Growing amount of evidence showed that synaptic dysfunctions are contributed to SCZ etiopathogenesis. The context and purpose of the study: Complexin-3, a presynaptic regulatory protein, represents here a special interest. This study was aimed to investigate the potential association of SCZ with rs3743487 single nucleotide polymorphism of the complexin-3 protein encoding gene (CPLX3). A total of 350 unrelated individuals of Armenian nationality (175 SCZ patients and the same number of age-, sex-matched healthy controls) were genotyped for the selected polymorphism using polymerase chain reaction with sequence-specific primers. Results and main findings: According to the results obtained, the frequency and carriage of the CPLX3 rs3743487*T allele did not differ in SCZ patients as compared to controls. Conclusions: We concluded that the CPLX3 rs3743487*T minor allele is not associated with SCZ in Armenian population. Brief summary: This study suggested no association of the CPLX3 rs3743487 polymorphism with schizophrenia, however, to clarify the role of the CPLX3 gene in SCZ further studies with much coverage of the gene and involvement of different methods are required.

Authors: Atshemyan Sofi, Zakharyan Roksana, Arakelyan Arsen

Date Published: 30th Dec 2015

Publication Type: Journal

Association of schizophrenia with variants of genes that encode transcription factors

Abstract (Expand)

Transcription factors c-Fos, c-Jun, and Ier5 are important regulators of neuronal plasticity and immune response. In the present work, several single nucleotide polymorphisms of the genes that encode … c-Fos-,c-Jun-, and Ier5 (FOS, JUN, and IER5, respectively) were investigated for potential association with schizophrenia. DNA samples obtained from patients with schizophrenia and healthy individuals were genotyped by polymerase chain reaction with allele-specific primers. It was shown that FOS rs1063169, FOS rs7101, JUN rs11688, and IER5 rs6425663 polymorphisms were associated with schizophrenia. In particular, the risk of schizophrenia was decreased in carriers of the minor alleles FOS rs1063169*T, JUN rs11688*A, and IER5 rs6425663*T, but increased in carriers of the FOS rs7101*T minor variant, especially in homozygotes.

Authors: A. S. Boyajyan, S. A. Atshemyan, R. V. Zakharyan

Date Published: 11th Dec 2015

Publication Type: Journal

Epigenetic Heterogeneity of B-Cell Lymphoma: Chromatin Modifiers.

Abstract (Expand)

We systematically studied the expression of more than fifty histone and DNA (de)methylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all … enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt's lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation.

Authors: Lydia Hopp, Lilit Nersisyan, Henry Löffler-Wirth, Arsen Arakelyan, Hans Binder

Date Published: 21st Oct 2015

Publication Type: Journal

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