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Identification of new HLA class I region genes by sample sequencing.

Although many human major histocompatibility genes have been identified, relatively few have been localized to the class I region. We searched for new class I region genes by sample sequencing, a process in which short stretches of random genomic sequence are generated from cosmids and then compared with sequences deposited in nucleotide databases. Four class I region cosmids were isolated for sample sequencing by screening a chromosome 6 specific cosmid library with probes derived from specific class I region genes or with overlapping class I region yeast artificial chromosomes. Cosmids were sonnicated to produce fragments of 0.5 - 1 kilobases, subcloned, and sequenced using an automated sequencer. Sequences were then compared with nucleotide sequences deposited in the GenBank databases using the BLASTN algorithm. A number of potential new class I region genes were identified, including a cDNA with similarity to the tre oncogene, the trans-activating factor SC1 (TCF19), and a member of the interferon inducible 1 - 8 gene family. These observations suggest that sample sequencing is an efficient method for identifying new class I region genes, which can be applied to other regions of the genome and to other species, and support previous observations that the class I region contains a variety of genes other than those encoding HLA antigens.

Base Sequence↗

Construction of a 'unigene' cDNA clone set by oligonucleotide fingerprinting allows access to 25 000 potential sugar beet genes.

Access to the complete gene inventory of an organism is crucial to understanding physiological processes like development, differentiation, pathogenesis, or adaptation to the environment. Transcripts from many active genes are present at low copy numbers. Therefore, procedures that rely on random EST sequencing or on normalisation and subtraction methods have to produce massively redundant data to get access to low-abundance genes. Here, we present an improved oligonucleotide fingerprinting (ofp) approach to the genome of sugar beet (Beta vulgaris), a plant for which practically no molecular information has been available. To identify distinct genes and to provide a representative 'unigene' cDNA set for sugar beet, 159 936 cDNA clones were processed utilizing large-scale, high-throughput data generation and analysis methods. Data analysis yielded 30 444 ofp clusters reflecting the number of different genes in the original cDNA sample. A sample of 10 961 cDNA clones, each representing a different cluster, were selected for sequencing. Standard sequence analysis confirmed that 89% of these EST sequences did represent different genes. These results indicate that the full set of 30 444 ofp clusters represent up to 25 000 genes. We conclude that the ofp analysis pipeline is an accurate and effective way to construct large representative 'unigene' sets for any plant of interest with no requirement for prior molecular sequence data.

Arabidopsis↗

Phytophthora functional genomics database (PFGD): functional genomics of phytophthora-plant interactions.

The Phytophthora Functional Genomics Database (PFGD; http://www.pfgd.org), developed by the National Center for Genome Resources in collaboration with The Ohio State University-Ohio Agricultural Research and Development Center (OSU-OARDC), is a publicly accessible information resource for Phytophthora-plant interaction research. PFGD contains transcript, genomic, gene expression and functional assay data for Phytophthora infestans, which causes late blight of potato, and Phytophthora sojae, which affects soybeans. Automated analyses are performed on all sequence data, including consensus sequences derived from clustered and assembled expressed sequence tags. The PFGD search filter interface allows intuitive navigation of transcript and genomic data organized by library and derived queries using modifiers, annotation keywords or sequence names. BLAST services are provided for libraries built from the transcript and genomic sequences. Transcript data visualization tools include Quality Screening, Multiple Sequence Alignment and Features and Annotations viewers. A genomic browser that supports comparative analysis via novel dynamic functional annotation comparisons is also provided. PFGD is integrated with the Solanaceae Genomics Database (SolGD; http://www.solgd.org) to help provide insight into the mechanisms of infection and resistance, specifically as they relate to the genus Phytophthora pathogens and their plant hosts.

Algal Proteins↗

The portable UNIX programming system (PUPS) and CANTOR: a computational environment for dynamical representation and analysis of complex neurobiological data.

Many problems in analytical biology, such as the classification of organisms, the modelling of macromolecules, or the structural analysis of metabolic or neural networks, involve complex relational data. Here, we describe a software environment, the portable UNIX programming system (PUPS), which has been developed to allow efficient computational representation and analysis of such data. The system can also be used as a general development tool for database and classification applications. As the complexity of analytical biology problems may lead to computation times of several days or weeks even on powerful computer hardware, the PUPS environment gives support for persistent computations by providing mechanisms for dynamic interaction and homeostatic protection of processes. Biological objects and their interrelations are also represented in a homeostatic way in PUPS. Object relationships are maintained and updated by the objects themselves, thus providing a flexible, scalable and current data representation. Based on the PUPS environment, we have developed an optimization package, CANTOR, which can be applied to a wide range of relational data and which has been employed in different analyses of neuroanatomical connectivity. The CANTOR package makes use of the PUPS system features by modifying candidate arrangements of objects within the system's database. This restructuring is carried out via optimization algorithms that are based on user-defined cost functions, thus providing flexible and powerful tools for the structural analysis of the database content. The use of stochastic optimization also enables the CANTOR system to deal effectively with incomplete and inconsistent data. Prototypical forms of PUPS and CANTOR have been coded and used successfully in the analysis of anatomical and functional mammalian brain connectivity, involving complex and inconsistent experimental data. In addition, PUPS has been used for solving multivariate engineering optimization problems and to implement the digital identification system (DAISY), a system for the automated classification of biological objects. PUPS is implemented in ANSI-C under the POSIX.1 standard and is to a great extent architecture- and operating-system independent. The software is supported by systems libraries that allow multi-threading (the concurrent processing of several database operations), as well as the distribution of the dynamic data objects and library operations over clusters of computers. These attributes make the system easily scalable, and in principle allow the representation and analysis of arbitrarily large sets of relational data. PUPS and CANTOR are freely distributed (http://www.pups.org.uk) as open-source software under the GNU license agreement.

Algorithms↗

De novo protein design: fully automated sequence selection.

The first fully automated design and experimental validation of a novel sequence for an entire protein is described. A computational design algorithm based on physical chemical potential functions and stereochemical constraints was used to screen a combinatorial library of 1.9 x 10(27) possible amino acid sequences for compatibility with the design target, a betabetaalpha protein motif based on the polypeptide backbone structure of a zinc finger domain. A BLAST search shows that the designed sequence, full sequence design 1 (FSD-1), has very low identity to any known protein sequence. The solution structure of FSD-1 was solved by nuclear magnetic resonance spectroscopy and indicates that FSD-1 forms a compact well-ordered structure, which is in excellent agreement with the design target structure. This result demonstrates that computational methods can perform the immense combinatorial search required for protein design, and it suggests that an unbiased and quantitative algorithm can be used in various structural contexts.

Algorithms↗

Building a knowledge base to support a digital library.

As part of an effort to develop a knowledge base to support searching online medical literature according to individual needs, we have studied the possibility of using the co-occurrence of MeSH terms in MEDLINE citations associated with the search strategies optimal for evidence based medicine to automated construction of a knowledge base. This study evaluates the relevance of the relationships between the semantic relationship pairs generated by the process, and the clinical validity of the semantic types involved in the process. From the semantic pairs proposed by our method, a group of clinicians judge sixty percent to be relevant. The remaining forty percent included semantic types considered unimportant by clinicians. The knowledge extraction method showed reasonable results. We believe it can be appropriate for the task of retrieving information from the medical record in order to guide users during a searching and retrieval process. Future directions include the validation of the knowledge, based on an evaluation of system performance.

Algorithms↗

Domino reactions for library synthesis of small molecules in combinatorial chemistry.

Domino reactions are highly efficient processes that allow the synthesis of complex molecules starting from simple substrates, in a straightforward fashion. The transformations are extremely useful for the design of small-molecule libraries by combinatorial chemistry if multicomponent domino reactions are employed. The reactions can be performed in solution, as well as on solid support, and give access to highly diverse molecules; in addition, their use in automated synthesis is possible.

Chemistry, Organic↗

Primer Prim'er: a web based server for automated primer design.

The Northeast Structural Genomics Consortium (NESG) is one of nine NIH-funded pilot projects created to develop technologies needed for structural studies of proteins on a genome-wide scale. One of the most challenging aspects of this emerging field is the production of protein samples amenable to structural determination. To do this efficiently, all steps in the protein production pipeline must be automated. Here we describe the Primer program (linked from http://www-nmr.cabm.rutgers.edu/bioinformatics, www-nmr.cabm.rutgers.edu/bioinformatics, a web-based primer design program freely available to the scientific community, which was created to automate this time consuming and laborious task. This program has the ability to simultaneously calculate plasmid specific primer sets for multiple open reading frame (ORF) targets, including 96-well and greater formats. Primer includes a library of commonly used plasmid systems and possesses the ability to upload user-defined plasmid systems. In addition to calculating gene-specific annealing regions for each target, the program also adds appropriate restriction endonuclease recognition or viral recombination sites while preserving a reading frame with plasmid based fusions. Primer has several useful features such as sorting calculated primer sets by target size, facilitating interpretation of PCR amplifications by agarose gel electrophoresis, as well as supplying the molecular biologist with many important characteristics of each target such as the expected size of the PCR amplified DNA fragment and internal restriction sites. The NESG has cloned over 1500 genes using oligonucleotide primers designed by Primer.

Computer-Aided Design↗

A comprehensive analysis of protein-protein interactions in Saccharomyces cerevisiae.

Two large-scale yeast two-hybrid screens were undertaken to identify protein-protein interactions between full-length open reading frames predicted from the Saccharomyces cerevisiae genome sequence. In one approach, we constructed a protein array of about 6,000 yeast transformants, with each transformant expressing one of the open reading frames as a fusion to an activation domain. This array was screened by a simple and automated procedure for 192 yeast proteins, with positive responses identified by their positions in the array. In a second approach, we pooled cells expressing one of about 6,000 activation domain fusions to generate a library. We used a high-throughput screening procedure to screen nearly all of the 6,000 predicted yeast proteins, expressed as Gal4 DNA-binding domain fusion proteins, against the library, and characterized positives by sequence analysis. These approaches resulted in the detection of 957 putative interactions involving 1,004 S. cerevisiae proteins. These data reveal interactions that place functionally unclassified proteins in a biological context, interactions between proteins involved in the same biological function, and interactions that link biological functions together into larger cellular processes. The results of these screens are shown here.

Fungal Proteins↗

Implementation of semi-automated cloning and prokaryotic expression screening: the impact of SPINE.

The implementation of high-throughput (HTP) cloning and expression screening in Escherichia coli by 14 laboratories in the Structural Proteomics In Europe (SPINE) consortium is described. Cloning efficiencies of greater than 80% have been achieved for the three non-ligation-based cloning techniques used, namely Gateway, ligation-indendent cloning of PCR products (LIC-PCR) and In-Fusion, with LIC-PCR emerging as the most cost-effective. On average, two constructs have been made for each of the approximately 1700 protein targets selected by SPINE for protein production. Overall, HTP expression screening in E. coli has yielded 32% soluble constructs, with at least one for 70% of the targets. In addition to the implementation of HTP cloning and expression screening, the development of two novel technologies is described, namely library-based screening for soluble constructs and parallel small-scale high-density fermentation.

Amino Acid Sequence↗

Protein-ribosome-mRNA display: affinity isolation of enzyme-ribosome-mRNA complexes and cDNA cloning in a single-tube reaction.

An enzyme-ribosome-mRNA complex was specifically purified by binding to the immobilized enzyme substrate and the cDNA was cloned in a single-tube reaction by one-step reverse transcription-PCR. The ganglioside GM3, used by sialyltransferase II (ST-II) as a substrate, was coated on a 96-well microtiter plate and ST-II was in vitro transcribed and translated from a cDNA library. The isolation of an enzyme-specific protein-ribosome (PRIME) complex was achieved with as little as 0.1 ng ST-II-specific cDNA in 5 microg of a total plasmid preparation or with the cDNA prepared from sublibraries previously inoculated at a density of 2000 clones/culture well. The affinity purification of the PRIME complex was highly specific for GM3 and did not result in cDNA amplification when a different ganglioside (GM1) was used for coating of the microtiter plate. The amplified cDNA was used for cloning or a second round of ribosome display, providing a fast analysis of enzyme affinity to multiple substrates. PRIME display can be used for host-free cDNA cloning from mRNA or cDNA libraries and for binding site mapping of the in vitro translated protein. The use of a single-tube reaction in ligand-coated microtiter plates indicates the versatility of PRIME display for cDNA cloning by automated procedures.

Chromatography, Affinity↗

Structural genomics for Caenorhabditis elegans: high throughput protein expression analysis.

The structural genomics initiatives have begun with the aim to create a so-called "basic set library" of protein folds that will be used to improve protein prediction methods. Such a library is thought to require the determination of up to 10,000 new structures, including representative structures of several sequence variants from each protein fold. To meet this goal in a reasonable time frame and cost, automated systems must be utilized to clone and to identify the soluble recombinant proteins contained in multiple genomes. This paper presents such a system, developed using the genome of Caenorhabditis elegans (19,099 genes) as a model eukaryotic organism for structural genomics. This system successfully automates nearly all aspects of recombinant protein expression analysis including subcloning, bacterial growth, recombinant protein expression, protein purification, and scoring protein solubility.

Animals↗

High-speed characterization and analysis of orange oils with tandem-column stop-flow GC and time-of-flight MS.

High-speed GC with time-of-flight (TOF) MS detection is used for the characterization and analysis of oils rendered from the peel of five diverse species of orange including bergemot orange, bitter orange, tangerine, mandarin orange, and sweet orange. With a user-defined signal-to-noise threshold of 100, 44 peaks were found and 36 compounds identified in the various oils. Some major constituent components show large concentration ranges over the five species. A 14-m-long, 0. 18-mm-i.d. column ensemble consisting of 7.0-m lengths of a trifluoropropylmethyl polysiloxane and a 5% phenyl dimethyl polysiloxane column was temperature-programmed at 50 degrees C/min starting at the time of injection to achieve analysis times under 140 s. The TOFMS was operated with a spectral acquisition rate of 25 spectra/s, and automated peak finding software successfully found all of the components, with the exception of one severely overlapping peak pair in bitter-orange oil. Of the 44 peaks, 25 were identified by use of a TOFMS library created for this study; another 11 were identified with a commercial terpene library, and 8 were not identified. A quantitative comparison (percent of total peak area) is presented for 16 components, which comprise 98.8-99.5% of the total peak area for the five orange species. Stop-flow operation of the column ensemble is used to enhance selectivity for targeted component pairs to facilitate single-channel detection for QA/ QC analysis of characterized samples and to enhance column selectivity for TOFMS characterization in cases in which peak overlap is so severe that only a single peak is observed.

Chromatography, Gas↗

SynCar: an approach to automated synthesis.

The automation of all aspects of manual solution-phase synthesis into one integrated, efficient, and reliable system could be regarded as something of an unmet challenge in organic chemistry. The requirements for modern solution-phase libraries in mainstream drug discovery is typically 50-250 high-purity compounds on a 10-100-mg scale, whether for target class libraries or lead optimization, and short cycle time in combination with high capacity is critical. To achieve these goals, in a codevelopment between Aventis and Accelab GmbH, Kusterdingen, Germany, we designed a completely novel system of independent workstations connected by a shuttle transfer system produced by Montech, Derendingen, Switzerland. Seven modular workstations process four reactions on each shuttle in parallel, with the ability to perform synthesis (temperature control and liquid reagent handling), filtration, liquid-liquid extraction, evaporation, weighing, solid-phase extraction, and HPLC/MS analysis. The modular design enables the continuous loading of shuttles at any time, and each shuttle can have its own workflow. The design also allows easy expansion for future needs. The result is a combination of high flexibility and high throughput.

Chemistry, Organic↗

Versatile Acylation of N-Nucleophiles Using a New Polymer-Supported 1-Hydroxybenzotriazole Derivative.

The synthesis of a new polymer-supported coupling reagent derived from 1-hydroxybenzotriazole is described. An aminomethylated polystyrene was functionalized by reaction with 3-nitro-4-chlorobenzenesulfonyl chloride (2) followed by treatement with hydrazine hydrate, to give the polymeric N-benzyl-1-hydroxybenzotriazole-6-sulfonamide (4).The polymeric reagent 4 was shown to be highly efficient for the synthesis of amides. The efficiency of 4 could be attributed to its high acidity, conferred by the sulfonyl moiety. The procedure for amide synthesis involves the formation of an activated ester on the derivatized polymer followed, in a second step, by treatment with an amine to generate the amide in solution. Simple filtration allows the separation of the product from the polymeric reagent which in this case plays the role of leaving group. An optimization study of this two-step procedure was performed. As amides are obtained in solution free of reaction byproducts, this method can be used in an automated procedure to recover them directly into a 96 well plate, ready to be used in high throughput screening assays. Thus 4 was shown to be particularly suitable for the high throughput parallel synthesis of amides libraries.

Journal Article↗

High density peptide microarrays. In situ synthesis and applications.

The technologies enabling the creation of large scale, miniaturized peptide or protein microarrays are emerging. The focuses of this review are the synthesis and applications of peptide and peptidomimetic microarrays, especially the light directed parallel synthesis of individually addressable high density peptide microarrays using a novel photogenerated reagent chemistry and digital photolithography (Gao et al., 1998, J. Am. Chem. Soc. 120, 12698; Pellois et al. 2002, Nat. Biotechnol. 20, 922). Concepts related to the synthesis are discussed, such as the reactions of photogenerated acids in the deprotection step of peptide synthesis or oligonucleotide synthesis, and the applications of high density peptide chips in antibody binding assays are discussed. Peptide chips provide versatile tools for probing antigen-antibody, protein-protein, peptide-ligand interactions and are basic components for miniaturization, automation, and system integration in research and clinical diagnosis applications.

Peptide Library↗