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At least 1,621 records · Page 90Linked to original sources

Comparative genomic hybridization in glioma: a meta-analysis of 509 cases.

Much data about genetic imbalances in tumors have been accumulated by comparative genomic hybridization (CGH). In order to distinguish between significantly and coincidentally involved regions in glioma by means of a meta-analysis, we summarized and analyzed the CGH results of 509 cases published in 26 reports between 1992 and 2001. The expansion of all aberrations to the 850-band level impressively visualized distinct patterns in astrocytoma, oligodendroglioma, and ependymoma as well as loci of frequent aberrations. For example, in astrocytoma the frequency of gains culminated at 7p12, 8q24.1, and 12q13-q15 (the loci of EGF-R, C-MYC and CDK4, respectively) and losses at 9p21 (the locus of p15 and p16) and 10q23.3 where PTEN resides. Most chromosomes were variably prone to copy number changes at different scales of aberrations. At the whole chromosome level the analysis showed +7, -10 in astrocytoma and +9, +18 in ependymoma, but +20q, -9p in astrocytoma and +1q, -22q in ependymoma at the p-q arm level. Furthermore, we could confirm the correlation between the average number of copy alterations per patient (average number of copy alterations [ANCA] index) and malignancy for astrocytoma in a refined graduation as well as for oligodendroglioma. As a new parameter, the average number of affected GTG-bands per patient (average number of affected GTG bands [ANAG] index) showed an even more striking correlation with the World Health Organization grade for gains and losses.

Astrocytoma↗

Genetic mapping in the major histocompatibility complex by restriction enzyme site polymorphisms: most mouse class I genes map to the Tla complex.

From a genomic library constructed from sperm DNA of the inbred BALB/c mouse, we previously isolated 54 cosmid clones that contain 36 class I genes and can be divided by restriction map analyses into 13 gene clusters. We have isolated single- and low-copy DNA probes from each of these clusters to visualize restriction enzyme site polymorphisms in the DNAs from various congeneic and recombinant congeneic mice. These polymorphisms permit us to map each of the 13 cosmid clusters to a precise location in the major histocompatibility complex of the mouse. Thirty-one of 36 class I genes map into the Tla complex of the major histocompatibility complex whereas the remaining 5 genes map to the H-2 complex. Thus, all 36 class I genes are located in the major histocompatibility complex. Analysis of the number of restriction enzyme fragments visualized by the single- and low-copy DNA probes suggests that the class I genes in different inbred strains of mice probably undergo gene duplications and deletions, presumably by homologous but unequal crossing-over.

Animals↗

Isolation and characterization of fission yeast sns mutants defective at the mitosis-to-interphase transition.

pim1-d1ts was previously identified in a visual screen for fission yeast mutants unable to complete the mitosis-to-interphase transition. pim1+ encodes the guanine nucleotide exchange factor (GEF) for the spi1 GTPase. Perturbations of this GTPase system by either mutation or overproduction of its regulatory proteins cause cells to arrest with postmitotic condensed chromosomes, an unreplicated genome, and a wide medial septum. The septation phenotype of pim1-d1ts was used as the basis for a more extensive screen for this novel class of sns (septated, not in S-phase) mutants. Seventeen mutants representing 14 complementation groups were isolated. Three strains, sns-A3, sns-A5, and sns-A6, representing two different alleles, are mutated in the pim1+ gene. Of the 13 non-pim1ts sns complementation groups, 11 showed genetic interactions with the spi1 GTPase system. The genes mutated in 10 sns strains were synthetically lethal with pim1-d1, and six sns strains were hypersensitive to overexpression of one or more of the known components of the spil GTPase system. Epistasis analysis places the action of the genes mutated in nine of these strains downstream of pim1+ and the action of one gene upstream of pim1+. Three strains, sns-A2, sns-B1, and sns-B9, showed genetic interaction with the spil GTPase system in every test performed. sns-B1 and sns-B9 are likely to identify downstream targets, whereas sns-A2 is likely to identify upstream regulators of the spi1 GTPase system that are required for the mitosis-to-interphase transition.

Alleles↗

Optimizing the detection of nascent transcripts by RNA fluorescence in situ hybridization.

An unusual feature of the mammalian genome is the number of genes exhibiting monoallelic expression. Recently random monoallelic expression of autosomal genes has been reported for olfactory and Ly-49 NK receptor genes, as well as for Il-2, Il-4 and Pax5. RNA fluorescence in situ hybridization (FISH) has been exploited to monitor allelic expression by visualizing the number of sites of transcription in individual nuclei. However, the sensitivity of this technique is difficult to determine for a given gene. We show that by combining DNA and RNA FISH it is possible to control for the hybridization efficiency and the accessibility and visibility of fluorescent probes within the nucleus.

Alleles↗

Electron microscopic evidence for splicing of Moloney murine leukemia virus RNAs.

Poly (A) containing RNA extracted from Moloney murine leukemia virus infected mouse cells was hybridized with long single-stranded complementary DNA, prepared in detergent disrupted virions. Visualization of the hybrids in the electron microscope revealed among the structures, circles and circles with tails. Measurements performed on the circular molecules revealed two major species with circumferences corresponding to 3 and 8.2 kilobases. The latter structures had identical size to circles obtained after annealing of cDNA with the viral genome, 35S RNA. Circularization of a small viral RNA (3 kb) from infected cells in the RNA-cDNA hybrids is a direct evidence that like the 35S RNA it shares similar nucleotide sequences at both the 5' and 3' ends. The presence of 5' end sequences common to the two RNA species indicates the existence of a spliced viral RNA. Furthermore, based on the circularization of viral RNA in the hybrids, we suggest a new way to quantitate and determine the lengths of spliced RNA in retrovirus infected cells.

Base Sequence↗

WEGO: a web tool for plotting GO annotations.

Unified, structured vocabularies and classifications freely provided by the Gene Ontology (GO) Consortium are widely accepted in most of the large scale gene annotation projects. Consequently, many tools have been created for use with the GO ontologies. WEGO (Web Gene Ontology Annotation Plot) is a simple but useful tool for visualizing, comparing and plotting GO annotation results. Different from other commercial software for creating chart, WEGO is designed to deal with the directed acyclic graph structure of GO to facilitate histogram creation of GO annotation results. WEGO has been used widely in many important biological research projects, such as the rice genome project and the silkworm genome project. It has become one of the daily tools for downstream gene annotation analysis, especially when performing comparative genomics tasks. WEGO, along with the two other tools, namely External to GO Query and GO Archive Query, are freely available for all users at http://wego.genomics.org.cn. There are two available mirror sites at http://wego2.genomics.org.cn and http://wego.genomics.com.cn. Any suggestions are welcome at wego@genomics.org.cn.

Genes↗

Association of matrix metalloproteinase-1 promoter polymorphism with generalized aggressive periodontitis in a Chinese population.

BACKGROUND: A single nucleotide polymorphism in the promoter region of -1607 bp of the human matrix metalloproteinase-1 (MMP-1) gene has been found to be associated with an increased risk of various inflammatory diseases and cancer metastasis. OBJECTIVES: The present study aimed to examine the distribution of MMP-1 genotypes in a group of Chinese subjects with generalized aggressive periodontitis and a group of periodontally healthy subjects, and to evaluate the possible association of the MMP-1 promoter polymorphism with aggressive periodontitis. METHODS: Genomic DNA was obtained from whole blood samples in 40 Chinese subjects with generalized aggressive periodontitis and 52 periodontally healthy subjects as controls. MMP-1 promoter fragment was amplified by polymerase chain reaction, and the polymorphisms were analyzed by restriction endonuclease cleavage. The alleles were detected by polyacrylamide gel electrophoresis and visualized with ethidium bromide. RESULTS: The detection frequency of 2G allele was significantly higher in the subjects with generalized aggressive periodontitis (68.7%) than in the control subjects (49%) (p < 0.01). The genotype of 2G/2G was found in 52.5% of the patients, which was significantly greater than that of control subjects (23.1%) (p < 0.05). CONCLUSION: The present study suggests that a single nucleotide polymorphism in the MMP-1 promoter region of -1607 bp may be associated with generalized aggressive periodontitis in Chinese population.

Adult↗

New (and used) approaches to the study of fungal pathogenicity.

The fungi are the most economically important plant pathogens and continue to be the focus of extensive research with a wide variety of methodologies. Enhancements in microscopy techniques have increased our ability to visualize the intimate interaction of fungi and their host plants. Improving methods allow pharmacological inhibition and genetic dissection of the determinants of fungal pathogenicity in a gene-by-gene approach. Identification and analysis of genes differentially transcribed in ways pertinent to pathogenicity continues to be a frequent research approach. Genome-wide analysis is gaining favor in biological research and fungal plant pathogens are no exception. Several industrial research groups are exploring fungal plant pathogenesis based on genomic sequence data and genome-wide mutagenesis. In March 2001 the first publicly available complete genome of a filamentous fungus (Neurospora crassa) was released. N. crassa is of course a saprophyte and there is no complete sequence available for a plant pathogenic fungus in public databases. However, freely accessible entire genome sequences for both plant pathogenic fungi and their hosts are on the horizon. Sequence availability promises to revolutionize the rate at which data relevant to disease processes will be accrued. In this review we describe approaches currently applied to the study of plant pathogenic fungi and explore developments of potential future benefit with existing technologies not yet applied to this group of important organisms.

Fungi↗

Impact of recombinant DNA technology and protein engineering on structure-based drug design: case studies of HIV-1 and HCMV proteases.

Structure-based drug design is an organized, multidisciplinary endeavor undertaken by scientists from many different scientific fields. The success of structure-based drug design was only made possible by advances in structure biology that provides the three-dimensional structure of the drug design target with which small molecular chemical ligands interact. Visualization of the conformation and interactions of a small molecule ligand bound to the protein target in the co-crystal structure of the protein:ligand complex enables the design of new chemical compounds with improved binding affinity and specificity. With the advances in molecular biology, lab automation, and computational science, genomic data have now become available for the human genome, as well as various other organisms. The pharmaceutical industry is currently putting forth tremendous effort in the area of functional genomics and structural genomics in attempts to decipher functions and structures of protein encoded by genes, with the ultimate goal of identifying novel targets for drug discovery and development. This chapter discusses the significant impact made by recombinant DNA technology and protein engineering on structural biology and, more specifically, on structure-based drug design.

Biotechnology↗

[Clonality study of palmar fibromatosis].

OBJECTIVE: To study the clonality of palmar fibromatosis by molecular genetic analysis of X chromosome inactivation pattern at a polymorphic site of human androgen receptor gene (HUMARA). METHODS: Twelve female cases of palmar fibromatosis were enrolled into this study. Hematoxylin and eosin-stained sections of paraffin-embedded, formalin-fixed tissues were microdissected by laser capture microdissection technology in order to obtain the proliferative spindle cells. Tumor cells isolated from rectal adenocarcinoma in a female patient were used as positive control. The genomic DNAs were extracted with phenol and chloroform, digested with methylation-sensitive restriction endonuclease HpaII, and amplified by polymerase chain reaction (PCR) using primers targeted to a highly polymorphic short tandem repeat of HUMARA. The amplimers were separated on vertical 8% non-denaturing polyacrylamide gels and the patterns were visualized with ethidium bromide stain. RESULTS: The methodology for clonality analysis was validated in the positive control using rectal adenocarcinoma cells. Among the 12 cases studied, PCR amplification failed in 3 samples and 1 sample showed homozygosity which was not suitable for further analysis. Eight samples were successfully amplified and showed a random X chromosome inactivation pattern, suggesting polyclonality in these lesions. CONCLUSIONS: Palmar fibromatosis is a polyclonal condition and should be considered as a form of non-neoplasmic fibroblastic proliferation.

Actins↗

Poxvirus Bioinformatics Resource Center: a comprehensive Poxviridae informational and analytical resource.

The Poxvirus Bioinformatics Resource Center (PBRC) has been established to provide informational and analytical resources to the scientific community to aid research directed at providing a better understanding of the Poxviridae family of viruses. The PBRC was specifically established as the result of the concern that variola virus, the causative agent of smallpox, as well as related viruses, might be utilized as biological weapons. In addition, the PBRC supports research on poxviruses that might be considered new and emerging infectious agents such as monkeypox virus. The PBRC consists of a relational database and web application that supports the data storage, annotation, analysis and information exchange goals of the project. The current release consists of over 35 complete genomic sequences of various genera, species and strains of viruses from the Poxviridae family. Sequence and annotation information for these viruses has been obtained from sequences publicly available from GenBank as well as sequences not yet deposited in GenBank that have been obtained from ongoing sequencing projects. In addition to sequence data, the PBRC provides comprehensive annotation and curation of virus genes; analytical tools to aid in the understanding of the available sequence data, including tools for the comparative analysis of different virus isolates; and visualization tools to help better display the results of various analyses. The PBRC represents the initial development of what will become a more comprehensive Viral Bioinformatics Resource Center for Biodefense that will be one of the National Institute of Allergy and Infectious Diseases' 'Bioinformatics Resource Centers for Biodefense and Emerging or Re-Emerging Infectious Diseases'. The PBRC website is available at http://www.poxvirus.org.

Computational Biology↗

Application of functional genomic technologies in a mouse model of retinal degeneration.

Generation of tissue-specific, normalized and subtracted cDNA libraries has the potential to characterize the expression of rare transcriptional units not represented on Affymetrix GeneChips. Initial sequence analysis of our murine cDNA clone collections showed that as much as 86, 45, and 30% of clones are not represented on the Affymetrix Mu11k, MG-U74, and MG-430 chip sets, respectively. A detailed study that compared EST sequences of a subtracted library generated from mouse retina to those of MG-430 consensus sequences was undertaken, using UniGene build 124 as the common reference. A set of 1111 nonredundant transcript regions, not represented on the commercial array, was identified. These clusters were used as the primary filter for analyzing a data set produced by assaying samples from the Pde6b(rd1) mouse model of retinal degeneration on a 12,325-feature retinal cDNA microarray. QRT-PCR validated eight unique transcripts identified by microarray. Seven of the transcripts showed retina-specific expression. Full-length cloning strategies were applied to two of the ESTs. The genes discovered by this approach are the full-length mouse homologue of guanylate cyclase 2F (GUCY2F) and a carboxy-truncated splice variant of retinal S-antigen (SAG), known as regulators of the visual phototransduction G-protein-coupled receptor-mediated signaling pathway. These sequences have been assigned GenBank Accession Nos. and , respectively.

Animals↗

Technicolour transgenics: imaging tools for functional genomics in the mouse.

Over the past decade, a battery of powerful tools that encompass forward and reverse genetic approaches have been developed to dissect the molecular and cellular processes that regulate development and disease. The advent of genetically-encoded fluorescent proteins that are expressed in wild type and mutant mice, together with advances in imaging technology, make it possible to study these biological processes in many dimensions. Importantly, these technologies allow direct visual access to complex events as they happen in their native environment, which provides greater insights into mammalian biology than ever before.

Animals↗

Expanded protein information at SGD: new pages and proteome browser.

The recent explosion in protein data generated from both directed small-scale studies and large-scale proteomics efforts has greatly expanded the quantity of available protein information and has prompted the Saccharomyces Genome Database (SGD; http://www.yeastgenome.org/) to enhance the depth and accessibility of protein annotations. In particular, we have expanded ongoing efforts to improve the integration of experimental information and sequence-based predictions and have redesigned the protein information web pages. A key feature of this redesign is the development of a GBrowse-derived interactive Proteome Browser customized to improve the visualization of sequence-based protein information. This Proteome Browser has enabled SGD to unify the display of hidden Markov model (HMM) domains, protein family HMMs, motifs, transmembrane regions, signal peptides, hydropathy plots and profile hits using several popular prediction algorithms. In addition, a physico-chemical properties page has been introduced to provide easy access to basic protein information. Improvements to the layout of the Protein Information page and integration of the Proteome Browser will facilitate the ongoing expansion of sequence-specific experimental information captured in SGD, including post-translational modifications and other user-defined annotations. Finally, SGD continues to improve upon the availability of genetic and physical interaction data in an ongoing collaboration with BioGRID by providing direct access to more than 82,000 manually-curated interactions.

Computer Graphics↗

Lytic growth of Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in culture.

Kaposi's sarcoma (KS) is the leading neoplasm of AIDS patients, and HIV infection is known to be a major risk factor for its development. However, KS can occur in the absence of HIV infection and the risk of KS development varies widely even among HIV-infected patients, with homosexual men with AIDS being 20 times more likely to develop KS than AIDS-afflicted children or hemophiliacs. These and other data strongly suggest that a sexually transmitted agent or co-factor may be involved in KS pathogenesis. Recently, DNA sequences corresponding to the genome of a novel member of the herpesvirus family have been identified within AIDS-KS biopsies, and several reports indicate that these sequences are also present in all forms of HIV-negative KS. These and other findings suggest this new agent, referred to as KS-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8), as a candidate for the putative etiologic cofactor. However, the role of this agent in KS remains hotly debated. Further progress in understanding its biology has been severely hampered by the lack of a cell culture system for virus growth. Here we report the development of a system for the lytic growth of this virus in a latently infected B cell line and present the first ultrastructural visualization of the virus. This system will facilitate the detailed study of the molecular biology of viral replication, the testing of antiviral drugs and the development of diagnostic tests for viral infection.

Acquired Immunodeficiency Syndrome↗

Whole-genome variance components linkage analysis using single-nucleotide polymorphisms versus microsatellites on quantitative traits of derived phenotypes from factor analysis of electroencephalogram waves.

Alcohol dependence is a serious public health problem. We studied data from families participating in the Collaborative Study on the Genetics of Alcoholism (COGA) and made available to participants in the Genetic Analysis Workshop 14 (GAW14) in order to search for genes predisposing to alcohol dependence. Using factor analysis, we identified four factors (F1, F2, F3, F4) related to the electroencephalogram traits. We conducted variance components linkage analysis with each of the factors. Our results using the Affymetrix single-nucleotide polymorphism dataset showed significant evidence for a novel linkage of F3 (factor comprised of the three midline channel EEG measures from the target case of the Visual Oddball experiment ttdt2, 3, 4) to chromosome 18 (LOD = 3.45). This finding was confirmed by analyses of the microsatellite data (LOD = 2.73) and Illumina SNP data (LOD = 3.30). We also demonstrated that, in a sample like the COGA data, a dense single-nucleotide polymorphism map provides better linkage signals than low-resolution microsatellite map with quantitative traits.

Chromosome Mapping↗

Homozygosity mapping of autosomal recessive retinitis pigmentosa locus (RP22) on chromosome 16p12.1-p12.3.

Autosomal recessive retinitis pigmentosa (arRP) is a genetically and clinically heterogeneous and progressive degenerative disorder of the retina, leading usually to severe visual handicap in adulthood. To date, disease loci/genes have been mapped/identified only in a minority of cases. DNA samples were collected from 20 large consanguineous Indian families, in which arRP segregated and that were suitable for homozygosity mapping of the disease locus. After excluding linkage to all known arRP loci, a genome-wide scan was initiated. In two families, homozygosity mapping, haplotype analysis, and linkage data mapped the disease locus (RP22) in an approximately 16-cM region between D16S287 and D16S420 on the proximal short arm of chromosome 16. No mutation has been found by direct sequencing in the gene (CRYM) encoding micron crystallin, which maps in the critical region.

Chromosome Mapping↗

The facile detection of the nt 1226 mutation of glucocerebrosidase by 'mismatched' PCR.

The most common Gaucher disease-producing mutation among Ashkenazi Jews is an A----G substitution at cDNA nt 1226 (genomic nt 5841). We describe a simple method for detecting this mutation both in genomic DNA and in cDNA by performing polymerase chain reaction (PCR) using a 5'-primer mismatched at one nucleotide so as to create an Xho I restriction site. When the mutation is present. the 105 bp fragment formed is cleaved to 89 and 16 nt fragments. The 89 bp fragment is easily visualized on a gel making it possible to distinguish individuals who do not have the mutation from heterozygotes and homozygotes.

Base Sequence↗