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Results for “protein function annotation”

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At least 1,441 records · Page 80Linked to original sources
PubMed2004

Genome annotation of a 1.5 Mb region of human chromosome 6q23 encompassing a quantitative trait locus for fetal hemoglobin expression in adults.

BACKGROUND: Heterocellular hereditary persistence of fetal hemoglobin (HPFH) is a common multifactorial trait characterized by a modest increase of fetal hemoglobin levels in adults. We previously localized a Quantitative Trait Locus for HPFH in an extensive Asian-Indian kindred to chromosome 6q23. As part of the strategy of positional cloning and a means towards identification of the specific genetic alteration in this family, a thorough annotation of the candidate interval based on a strategy of in silico / wet biology approach with comparative genomics was conducted. RESULTS: The ~1.5 Mb candidate region was shown to contain five protein-coding genes. We discovered a very large uncharacterized gene containing WD40 and SH3 domains (AHI1), and extended the annotation of four previously characterized genes (MYB, ALDH8A1, HBS1L and PDE7B). We also identified several genes that do not appear to be protein coding, and generated 17 kb of novel transcript sequence data from re-sequencing 97 EST clones. CONCLUSION: Detailed and thorough annotation of this 1.5 Mb interval in 6q confirms a high level of aberrant transcripts in testicular tissue. The candidate interval was shown to exhibit an extraordinary level of alternate splicing - 19 transcripts were identified for the 5 protein coding genes, but it appears that a significant portion (14/19) of these alternate transcripts did not have an open reading frame, hence their functional role is questionable. These transcripts may result from aberrant rather than regulated splicing.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2026

Preliminary Exploration on Melatonin-Mediated Protective Effects in Intracranial Aneurysms: Transcriptomic, Proteomic, and Metabolomic Profiling of Cerebral Vascular Tissues Combined with in vivo Animal Experiments.

BACKGROUND: Intracranial aneurysm (IA) is a life-threatening cerebrovascular disease with unclear molecular mechanisms and limited drug treatment. Our previous research has shown that melatonin (MLT) has potential protective effects in IA, but its mechanism remains unclear. The purpose of this study is to explore the pathological mechanism of IA and the therapeutic mechanism of MLT by integrating transcriptomic, proteomic and metabolomic analyses. METHODS: In this study, mouse models of IA were successfully established by combining elastase injection with angiotensin II infusion. C57BL/6 mice were divided into control, IA model, IA model+MLT, and IA model+nimodipine groups. The pathological conditions were evaluated by hematoxylin-eosin (HE) staining, TUNEL staining, and scanning electron microscopy. Transcriptomic (n=3 for each group), proteomic (n=3 for each group), and metabolomic (n=6 for each group) analyses were performed based on cerebral vascular tissue samples. The screening thresholds for differentially expressed genes and differentially expressed proteins were P <0.05 and fold change >1.5 and fold change <0.667. The screening criteria for differential metabolites were variable importance for the projection (VIP)> 1.0, fold change >1.2 and fold change <0.833, and P <0.05. RESULTS: MLT alleviated brain tissue damage, vascular endothelial damage, structural disruption, and apoptosis in IA mice. Transcriptomic, proteomic and metabolomic analyses identified numerous differential molecules. Functional annotation revealed that these molecules may be involved in biological pathways and processes such as immune inflammation, vascular remodeling, extracellular matrix remodeling, neuropeptide activity, oxidative stress and metabolic pathways, thereby regulating the occurrence and development of IA or mediating the therapeutic effects of MLT. Furthermore, transcriptomic and proteomic analyses also suggest that there may be extensive post-transcriptional, translational and post-translational regulatory events in the progression of IA and the therapeutic effects of MLT. Integrated transcriptomic and proteomic analyses suggest that Npy may be a key molecule in regulating IA progression and mediating MLT therapeutic effects, and its potential value is further supported by our immunohistochemical validation results. CONCLUSION: Multi-omics integrative analysis preliminarily revealed that the potential mechanisms of MLT may involve the regulation of inflammatory response, vascular remodeling, extracellular matrix remodeling, neuropeptide activity, oxidative stress, metabolic pathways, and post-transcriptional/translational regulation.

Animals↗
PubMed2003

DAVID: Database for Annotation, Visualization, and Integrated Discovery.

BACKGROUND: Functional annotation of differentially expressed genes is a necessary and critical step in the analysis of microarray data. The distributed nature of biological knowledge frequently requires researchers to navigate through numerous web-accessible databases gathering information one gene at a time. A more judicious approach is to provide query-based access to an integrated database that disseminates biologically rich information across large datasets and displays graphic summaries of functional information. RESULTS: Database for Annotation, Visualization, and Integrated Discovery (DAVID; http://www.david.niaid.nih.gov) addresses this need via four web-based analysis modules: 1) Annotation Tool - rapidly appends descriptive data from several public databases to lists of genes; 2) GoCharts - assigns genes to Gene Ontology functional categories based on user selected classifications and term specificity level; 3) KeggCharts - assigns genes to KEGG metabolic processes and enables users to view genes in the context of biochemical pathway maps; and 4) DomainCharts - groups genes according to PFAM conserved protein domains. CONCLUSIONS: Analysis results and graphical displays remain dynamically linked to primary data and external data repositories, thereby furnishing in-depth as well as broad-based data coverage. The functionality provided by DAVID accelerates the analysis of genome-scale datasets by facilitating the transition from data collection to biological meaning.

Computational Biology↗
PubMed2006

A functional dlt operon, encoding proteins required for incorporation of d-alanine in teichoic acids in gram-positive bacteria, confers resistance to cationic antimicrobial peptides in Streptococcus pneumoniae.

Streptococcus pneumoniae is one of the few species within the group of low-G +C gram-positive bacteria reported to contain no d-alanine in teichoic acids, although the dltABCD operon encoding proteins responsible for d-alanylation is present in the genomes of two S. pneumoniae strains, the laboratory strain R6 and the clinical isolate TIGR4. The annotation of dltA in R6 predicts a protein, d-alanine-d-alanyl carrier protein ligase (Dcl), that is shorter at the amino terminus than all other Dcl proteins. Translation of dltA could also start upstream of the annotated TTG start codon at a GTG, resulting in the premature termination of dltA translation at a stop codon. Applying a novel integrative translation probe plasmid with Escherichia coli 'lacZ as a reporter, we could demonstrate that dltA translation starts at the upstream GTG. Consequently, S. pneumoniae R6 is a dltA mutant, whereas S. pneumoniae D39, the parental strain of R6, and Rx, another derivative of D39, contained intact dltA genes. Repair of the stop codon in dltA of R6 and insertional inactivation of dltA in D39 and Rx yielded pairs of dltA-deficient and dltA-proficient strains. Subsequent phenotypic analysis showed that dltA inactivation resulted in enhanced sensitivity to the cationic antimicrobial peptides nisin and gallidermin, a phenotype fully consistent with those of dltA mutants of other gram-positive bacteria. In addition, mild alkaline hydrolysis of heat-inactivated whole cells released d-alanine from dltA-proficient strains, but not from dltA mutants. The results of our study suggest that, as in many other low-G+C gram-positive bacteria, teichoic acids of S. pneumoniae contain d-alanine residues in order to protect this human pathogen against the actions of cationic antimicrobial peptides.

Alanine↗
PubMed2005

Functional genomic analysis of C. elegans molting.

Although the molting cycle is a hallmark of insects and nematodes, neither the endocrine control of molting via size, stage, and nutritional inputs nor the enzymatic mechanism for synthesis and release of the exoskeleton is well understood. Here, we identify endocrine and enzymatic regulators of molting in C. elegans through a genome-wide RNA-interference screen. Products of the 159 genes discovered include annotated transcription factors, secreted peptides, transmembrane proteins, and extracellular matrix enzymes essential for molting. Fusions between several genes and green fluorescent protein show a pulse of expression before each molt in epithelial cells that synthesize the exoskeleton, indicating that the corresponding proteins are made in the correct time and place to regulate molting. We show further that inactivation of particular genes abrogates expression of the green fluorescent protein reporter genes, revealing regulatory networks that might couple the expression of genes essential for molting to endocrine cues. Many molting genes are conserved in parasitic nematodes responsible for human disease, and thus represent attractive targets for pesticide and pharmaceutical development.

Animals↗
PubMed2004

CREB binds to multiple loci on human chromosome 22.

The cyclic AMP-responsive element-binding protein (CREB) is an important transcription factor that can be activated by hormonal stimulation and regulates neuronal function and development. An unbiased, global analysis of where CREB binds has not been performed. We have mapped for the first time the binding distribution of CREB along an entire human chromosome. Chromatin immunoprecipitation of CREB-associated DNA and subsequent hybridization of the associated DNA to a genomic DNA microarray containing all of the nonrepetitive DNA of human chromosome 22 revealed 215 binding sites corresponding to 192 different loci and 100 annotated potential gene targets. We found binding near or within many genes involved in signal transduction and neuronal function. We also found that only a small fraction of CREB binding sites lay near well-defined 5' ends of genes; the majority of sites were found elsewhere, including introns and unannotated regions. Several of the latter lay near novel unannotated transcriptionally active regions. Few CREB targets were found near full-length cyclic AMP response element sites; the majority contained shorter versions or close matches to this sequence. Several of the CREB targets were altered in their expression by treatment with forskolin; interestingly, both induced and repressed genes were found. Our results provide novel molecular insights into how CREB mediates its functions in humans.

Binding Sites↗
PubMed2026

Divergent evolutionary strategies in spider venoms: A comparative proteomic profiling of four sympatric species from Yunnan.

Spider venoms comprise complex cocktails of bioactive molecules evolved for predation and defense, representing a valuable resource for biological research and pharmaceutical discovery. In this study, we performed a systematic analysis of venom gland extracts from four common spider species indigenous to Yunnan, China: Agelena limbata, Hippasa lycosina, Lycosa grahami, and Sinopoda pengi. Using an integrated transcriptomic and proteomic targeted profiling approach, we successfully annotated 141 distinct toxins. Comparative analysis revealed significant interspecific heterogeneity, suggesting distinct evolutionary trajectories and "weapon system economics." Both A. limbata and L. grahami exhibited a "peptide-dominant" profile anchored by neurotoxic peptides and isomerases, optimized for rapid chemical paralysis. In contrast, S. pengi displayed a distinct "protein-dominant" signature enriched with high-molecular-weight enzymes and CAP superfamily proteins, likely functioning to facilitate tissue degradation and toxin diffusion. Occupying an intermediate position, H. lycosina demonstrated a hybrid composition. These findings suggest that although these species share the same geographical range, their venom systems have undergone divergent evolutionary adaptations driven by specific ecological niches and hunting strategies. This study represents the first systematic proteomic characterization of these venom components, providing a valuable reservoir of molecular candidates while highlighting the bioinformatic nuances of analyzing whole-gland homogenates.

Animals↗
PubMed2004

HIVbase: a PC/Windows-based software offering storage and querying power for locally held HIV-1 genetic, experimental and clinical data.

BACKGROUND: Human immunodeficiency virus (HIV) research involves ongoing, repetitious sequencing of the HIV genome and the massive accumulation of associated investigational data. As a result, the storage of annotated DNA and/or protein sequences, as well as information retrieval, have become increasingly difficult tasks, with scientists extracting less information from their collected data than they should. OBJECTIVES: Our objective was to design and develop a software package to aid researchers in the storage, analysis and exploration of their HIV-associated data. RESULTS: HIVbase contains familiar, easy-to-use interfaces and functionality for integrating many types of disparate data. The software contains tools that allow for the mass import of raw genetic data, eliminate repetitious sequence translations, have the ability to identify automatically and store HIV regions of interest from nucleic acid or protein sequences, allow for the export of data in commonly used analysis-ready formats, and for unique querying approaches.

Algorithms↗
PubMed2006

FlyTF: a systematic review of site-specific transcription factors in the fruit fly Drosophila melanogaster.

SUMMARY: We present a manually annotated catalogue of site-specific transcription factors (TFs) in the fruit fly Drosophila melanogaster. These were identified from a list of candidate proteins with transcription-related Gene Ontology (Go) annotation as well as structural DNA-binding domain assignments. For all 1052 candidate proteins, a defined set of rules was applied to classify information from the literature and computational data sources with respect to both DNA-binding and transcriptional regulatory properties. We propose a set of 753 TFs in the fruit fly, of which 23 are confident novel predictions of this function for previously uncharacterized proteins.

Animals↗
PubMed2002

GeneNet: a database on structure and functional organisation of gene networks.

The GeneNet database is designed for accumulation of information on gene networks. Original technology applied in GeneNet enables description of not only a gene network structure and functional relationships between components, but also metabolic and signal transduction pathways. Specialised software, GeneNet Viewer, automatically displays the graphical diagram of gene networks described in the database. Current release 3.0 of GeneNet database contains descriptions of 25 gene networks, 945 proteins, 567 genes, 151 other substances and 1364 relationships between components of gene networks. Information distributed between 14 interlinked tables was obtained by annotating 968 scientific publications. The SRS-version of GeneNet database is freely available (http://wwwmgs.bionet.nsc.ru/mgs/systems/genenet/).

Animals↗
PubMed2006

Analysing the developing brain transcriptome with the GenePaint platform.

We discuss technical means by which the complexity of gene and protein signalling cascades can be projected onto the complex structure of the mammalian brain. We argue that this requires both robotics and novel computational tools to register images of gene expression, annotate expression patterns and quantify gene expression. When sufficiently enriched and detailed, such gene expression/neuroanatomical atlases are hypothesis-generating tools and contain in themselves much of the information needed to investigate function in normal and genetically or otherwise modified brains. To be successful and useful, data-rich and comprehensive gene expression/neuroanatomical atlases have to be web accessible and structured in a way that allows the application of data exploration and mining tools.

Animals↗
PubMed2003

Development of a Listeria monocytogenes EGDe partial proteome reference map and comparison with the protein profiles of food isolates.

A partially annotated proteome reference map of the food pathogen Listeria monocytogenes was developed for exponentially growing cells under standardized, optimal conditions by using the sequenced strain EGDe (serotype 1/2a) as a model organism. The map was developed by using a reproducible total protein extraction and two-dimensional (2-D) polyacrylamide gel electrophoresis analysis procedure, and it contained 33 identified proteins representing the four main protein functional classes. In order to facilitate analysis of membrane proteins, a protein compartmentalization procedure was assessed. The method used provided partial fractionation of membrane and cytosolic proteins. The total protein 2-D profiles of three serotype 1/2a strains and one serotype 1/2b strain isolated from food were compared to the L. monocytogenes EGDe proteome. An average of 13% of the major protein spots in the food strain proteomes were not matched in the strain EGDe proteome. The variation was greater for the less intense spots, and on average 28% of these spots were not matched. Two of the proteins identified in L. monocytogenes EGDe were missing in one or more of the food isolates. These two proteins were proteins involved in the main glycolytic pathway and in metabolism of coenzymes and prosthetic groups. The two corresponding genes were found by PCR amplification to be present in the four food isolates. Our results show that the L. monocytogenes EGDe reference map is a valuable starting point for analyses of strains having various origins and could be useful for analyzing the proteomes of different isolates of this pathogen.

Animals↗
PubMed2005

Molecular models of NS3 protease variants of the Hepatitis C virus.

BACKGROUND: Hepatitis C virus (HCV) currently infects approximately three percent of the world population. In view of the lack of vaccines against HCV, there is an urgent need for an efficient treatment of the disease by an effective antiviral drug. Rational drug design has not been the primary way for discovering major therapeutics. Nevertheless, there are reports of success in the development of inhibitor using a structure-based approach. One of the possible targets for drug development against HCV is the NS3 protease variants. Based on the three-dimensional structure of these variants we expect to identify new NS3 protease inhibitors. In order to speed up the modeling process all NS3 protease variant models were generated in a Beowulf cluster. The potential of the structural bioinformatics for development of new antiviral drugs is discussed. RESULTS: The atomic coordinates of crystallographic structure 1CU1 and 1DY9 were used as starting model for modeling of the NS3 protease variant structures. The NS3 protease variant structures are composed of six subdomains, which occur in sequence along the polypeptide chain. The protease domain exhibits the dual beta-barrel fold that is common among members of the chymotrypsin serine protease family. The helicase domain contains two structurally related beta-alpha-beta subdomains and a third subdomain of seven helices and three short beta strands. The latter domain is usually referred to as the helicase alpha-helical subdomain. The rmsd value of bond lengths and bond angles, the average G-factor and Verify 3D values are presented for NS3 protease variant structures. CONCLUSIONS: This project increases the certainty that homology modeling is an useful tool in structural biology and that it can be very valuable in annotating genome sequence information and contributing to structural and functional genomics from virus. The structural models will be used to guide future efforts in the structure-based drug design of a new generation of NS3 protease variants inhibitors. All models in the database are publicly accessible via our interactive website, providing us with large amount of structural models for use in protein-ligand docking analysis.

Amino Acid Sequence↗
PubMed2005

The expression pattern of the Drosophila vesicular glutamate transporter: a marker protein for motoneurons and glutamatergic centers in the brain.

To determine the functions of genes in distinct tissues during the development of Drosophila, it is often desirable to have genetic tools for targeted gene expression in restricted subsets of cells. Here, we report the identification of the enhancer trap line OK371-Gal4, which is expressed in a defined subset of neurons from embryonic stage 15 to adulthood. In the ventral nerve chord, it is expressed almost exclusively in motoneurons and in the brain in a limited number of neuronal clusters. The OK371 enhancer trap element is inserted in the proximity of the annotated gene CG9887, which encodes a Drosophila vesicular glutamate transporter (DVGLUT). In situ hybridization experiments using antisense probes against the mRNAs of DVGLUT and neighboring genes confirm that OK371-Gal4 detects an enhancer of DVGLUT. DVGLUT-specific antibodies detect its expression in identifiable motoneurons, which are known to be glutamatergic in Drosophila. DVGLUT initially appears in small cytoplasmic punctae in the somata of these motoneurons. As development proceeds, DVGLUT-positive particles are transported along motor axons and become concentrated at neuromuscular junctions (NMJs), where they colocalize with the synaptic vesicle marker synaptotagmin. We find that the DVGLUT-specific antibodies are valuable tools for the identification of motoneurons and other glutamatergic neurons. In addition, the OK371-Gal4 line can be used for the targeted expression of any gene in these cells. Given that vesicular glutamate transporters are essential for the uptake of the neurotransmitter glutamate into synaptic vesicles these tools provide a means to test gene function in these functionally important neurons.

Amino Acid Sequence↗
PubMed2003

Integrating 'omic' information: a bridge between genomics and systems biology.

The availability of genome sequences for several organisms, including humans, and the resulting first-approximation lists of genes, have allowed a transition from molecular biology to 'modular biology'. In modular biology, biological processes of interest, or modules, are studied as complex systems of functionally interacting macromolecules. Functional genomic and proteomic ('omic') approaches can be helpful to accelerate the identification of the genes and gene products involved in particular modules, and to describe the functional relationships between them. However, the data emerging from individual omic approaches should be viewed with caution because of the occurrence of false-negative and false-positive results and because single annotations are not sufficient for an understanding of gene function. To increase the reliability of gene function annotation, multiple independent datasets need to be integrated. Here, we review the recent development of strategies for such integration and we argue that these will be important for a systems approach to modular biology.

Computational Biology↗
PubMed2005

Bacterial phytopathogens and genome science.

There are now fourteen completed genomes of bacterial phytopathogens, all of which have been generated in the past six years. These genomes come from a phylogenetically diverse set of organisms, and range in size from 870 kb to more than 6Mb. The publication of these annotated genomes has significantly helped our understanding of bacterial plant disease. These genomes have also provided important information about bacterial evolution. Examples of recently completed genomes include: Pseudomonas syringae pv tomato, which is notable for its large repertoire of effector proteins; Leifsonia xyli subsp. xyli, the first Gram-positive bacterial genome to be sequenced; and Phytoplasma asteris, the small genome that lacks important functions previously thought to be essential in a bacterium.

Actinomycetales↗
PubMed2003

RNABase: an annotated database of RNA structures.

RNABase is a unified database of all three-dimensional structures containing RNA deposited in either the Protein Data Bank (PDB) or Nucleic Acid Data Base (NDB). For each structure, RNABase contains a brief summary as well as annotation of conformational parameters, identification of possible model errors, Ramachandran-style conformational maps and classification of ribonucleotides into conformers. These same analyses can also be performed on structures submitted by users. To facilitate access, structures are automatically placed into a variety of functional and structural categories, including: ribozymes, pseudoknots, etc. RNABase can be freely accessed on the web at http://www.rnabase.org. We are committed to maintaining this database indefinitely.

Databases, Nucleic Acid↗
PubMed2000

Computational tools for protein modeling.

Protein modeling is playing a more and more important role in protein and peptide sciences due to improvements in modeling methods, advances in computer technology, and the huge amount of biological data becoming available. Modeling tools can often predict the structure and shed some light on the function and its underlying mechanism. They can also provide insight to design experiments and suggest possible leads for drug design. This review attempts to provide a comprehensive introduction to major computer programs, especially on-line servers, for protein modeling. The review covers the following aspects: (1) protein sequence comparison, including sequence alignment/search, sequence-based protein family classification, domain parsing, and phylogenetic classification; (2) sequence annotation, including annotation/prediction of hydrophobic profiles, transmembrane regions, active sites, signaling sites, and secondary structures; (3) protein structure analysis, including visualization, geometry analysis, structure comparison/classification, dynamics, and electrostatics; (4) three-dimensional structure prediction, including homology modeling, fold recognition using threading, ab initio prediction, and docking. We will address what a user can expect from the computer tools in terms of their strengths and limitations. We will also discuss the major challenges and the future trends in the field. A collection of the links of tools can be found at http://compbio.ornl.gov/structure/resource/.

Algorithms↗