Browsing by Subject "Gene function"

Now showing 1 - 7 of 7

Open Access
Characterization of a novel zebrafish (Danio rerio) gene, wdr81, associated with cerebellar ataxia, mental retardation and dysequilibrium syndrome (CAMRQ)
(BioMed Central Ltd., 2015) Doldur-Balli, F.; Ozel, M. N.; Gulsuner, S.; Tekinay, A. B.; Ozcelik, T.; Konu, O.; Adams, M. M.
Background: WDR81 (WD repeat-containing protein 81) is associated with cerebellar ataxia, mental retardation and disequilibrium syndrome (CAMRQ2, [MIM 610185]). Human and mouse studies suggest that it might be a gene of importance during neurodevelopment. This study aimed at fully characterizing the structure of the wdr81 transcript, detecting the possible transcript variants and revealing its expression profile in zebrafish, a powerful model organism for studying development and disease. Results: As expected in human and mouse orthologous proteins, zebrafish wdr81 is predicted to possess a BEACH (Beige and Chediak-Higashi) domain, a major facilitator superfamily domain and WD40-repeats, which indicates a conserved function in these species. We observed that zebrafish wdr81 encodes one open reading frame while the transcript has one 5' untranslated region (UTR) and the prediction of the 3' UTR was mainly confirmed along with a detected insertion site in the embryo and adult brain. This insertion site was also found in testis, heart, liver, eye, tail and muscle, however, there was no amplicon in kidney, intestine and gills, which might be the result of possible alternative polyadenylation processes among tissues. The 5 and 18 hpf were critical timepoints of development regarding wdr81 expression. Furthermore, the signal of the RNA probe was stronger in the eye and brain at 18 and 48 hpf, then decreased at 72 hpf. Finally, expression of wdr81 was detected in the adult brain and eye tissues, including but not restricted to photoreceptors of the retina, presumptive Purkinje cells and some neurogenic brains regions. Conclusions: Taken together these data emphasize the importance of this gene during neurodevelopment and a possible role for neuronal proliferation. Our data provide a basis for further studies to fully understand the function of wdr81.
Open Access
mESAdb: microRNA expression and sequence analysis database
(Oxford University Press, 2011) Kaya, Koray D.; Karakülah, G.; Yakıcıer, Cengiz M.; Acar, Aybar C.; Konu, Özlen
MicroRNA expression and sequence analysis database (http://konulab.fen. bilkent.edu.tr/mirna/) (mESAdb) is a regularly updated database for the multivariate analysis of sequences and expression of microRNAs from multiple taxa. mESAdb is modular and has a user interface implemented in PHP and JavaScript and coupled with statistical analysis and visualization packages written for the R language. The database primarily comprises mature microRNA sequences and their target data, along with selected human, mouse and zebrafish expression data sets. mESAdb analysis modules allow (i) mining of microRNA expression data sets for subsets of microRNAs selected manually or by motif; (ii) pair-wise multivariate analysis of expression data sets within and between taxa; and (iii) association of microRNA subsets with annotation databases, HUGE Navigator, KEGG and GO. The use of existing and customized R packages facilitates future addition of data sets and analysis tools. Furthermore, the ability to upload and analyze user-specified data sets makes mESAdb an interactive and expandable analysis tool for microRNA sequence and expression data.
Open Access
An ontology for collaborative construction and analysis of cellular pathways
(Oxford University Press, 2004-02-12) Demir, Emek; Babur, Özgün; Doğrusöz, Uğur; Gürsoy, Atilla; Ayaz, Aslı; Güleşır, Gürcan; Nişancı, Gürkan; Çetin Atalay, Rengül
Motivation: As the scientific curiosity in genome studies shifts toward identification of functions of the genomes in large scale, data produced about cellular processes at molecular level has been accumulating with an accelerating rate. In this regard, it is essential to be able to store, integrate, access and analyze this data effectively with the help of software tools. Clearly this requires a strong ontology that is intuitive, comprehensive and uncomplicated. Results: We define an ontology for an intuitive, comprehensive and uncomplicated representation of cellular events. The ontology presented here enables integration of fragmented or incomplete pathway information via collaboration, and supports manipulation of the stored data. In addition, it facilitates concurrent modifications to the data while maintaining its validity and consistency. Furthermore, novel structures for representation of multiple levels of abstraction for pathways and homologies is provided. Lastly, our ontology supports efficient querying of large amounts of data. We have also developed a software tool named pathway analysis tool for integration and knowledge acquisition (PATIKA) providing an integrated, multi-user environment for visualizing and manipulating network of cellular events. PATIKA implements the basics of our ontology. © Oxford University Press 2004; All rights reserved.
Open Access
PATIKA: an integrated visual environment for collaborative construction and analysis of cellular pathways
(Oxford University Press, 2002-06) Demir, Emek; Babur, Özgün; Doğrusöz, Uğur; Gürsoy, Atilla; Nişancı, Gürkan; Çetin Atalay, Rengül; Öztürk, Mehmet
Motivation: Availability of the sequences of entire genomes shifts the scientific curiosity towards the identification of function of the genomes in large scale as in genome studies. In the near future, data produced about cellular processes at molecular level will accumulate with an accelerating rate as a result of proteomics studies. In this regard, it is essential to develop tools for storing, integrating, accessing, and analyzing this data effectively. Results: We define an ontology for a comprehensive representation of cellular events. The ontology presented here enables integration of fragmented or incomplete pathway information and supports manipulation and incorporation of the stored data, as well as multiple levels of abstraction. Based on this ontology, we present the architecture of an integrated environment named PATIKA (Pathway Analysis Tool for Integration and Knowledge Acquisition). PATIKA is composed of a server-side, scalable, object-oriented database and client-side editors to provide an integrated, multi-user environment for visualizing and manipulating network of cellular events. This tool features automated pathway layout, functional computation support, advanced querying and a user-friendly graphical interface. We expect that PATIKA will be a valuable tool for rapid knowledge acquisition, microarray generated large-scale data interpretation, disease gene identification, and drug development.
Open Access
PATIKA: an integrated visual environment for collaborative construction and analysis of cellular pathways
(American Society for Biochemistry and Molecular Biology(ASBMB), 2002-09) Demir, Emek; Babur, Özgün; Doğrusöz, Uğur; Gürsoy, Atilla; Nişancı, Gürkan; Çetin Atalay, Rengül; Öztürk, Mehmet
Open Access
TP53 mutations in familial breast cancer: Functional aspects
(John Wiley & Sons, Inc., 2003) Gasco, M.; Yulug, I. G.; Crook, T.
Mutation in p53 (TP53) remains one of the most commonly described genetic events in human neoplasia. The occurrence of mutations is somewhat less common in sporadic breast carcinomas than in other cancers, with an overall frequency of about 20%. There is, however, evidence that p53 is mutated at a significantly higher frequency in breast carcinomas arising in carriers of germ-line BRCA1 and BRCA2 mutations. Some of the p53 mutants identified in BRCA1 and BRCA2 mutation carriers are either previously undescribed or infrequently reported in sporadic human cancers. Functional characterization of such mutants in various systems has revealed that they frequently possess properties not commonly associated with those occurring in sporadic cases: they retain apoptosis-inducing, transactivating, and growth-inhibitory activities similar to the wild-type protein, yet are compromised for transformation suppression and also possess an independent transforming phenotype. The occurrence of such mutants in familial breast cancer implies the operation of distinct selective pressures during tumorigenesis in BRCA-associated breast cancers.
Open Access
Zebrafish xenotransplantation models for studying gene function and drug treatment in hepatocellular carcinoma
(2022-01-15) Konu, Ozlen; Targen, Seniye
Introduction Zebrafish is a promising model organism for human disease including hepatocellular cancer (HCC). Recently, zebrafish has emerged also as a host for xenograft studies of liver cancer cell lines and patient derived tumors of HCC. Zebrafish embryos enable drug screening and gene function studies of xenografted cells via ease of microinjection and visualization of tumor growth and metastasis. Objectives In this review, we aimed to overview zebrafish HCC and liver cancer xenotransplantation studies focusing on ‘gene functional analysis’ and ‘drug/chemical screening’. Methods Herein, a comprehensive literature search was performed for liver and HCC xenografts in zebrafish on PubMed using different key words and filters for molecular modifications or drug exposure. Results Our literature search revealed around 250 studies which were filtered and summarized in a table (Table 1) revealing comprehensive collection of experimental and technical details on microinjection, injected cell lines, molecular modifications of injected cells, types and doses of drug treatments as well as biological assessments. Conclusion This review provides a platform for HCC and liver xenografts and highlights studies performed to understand gene functionality and drug efficacy in vivo in zebrafish.