Proteine sind Makromoleküle, deren Monomereinheiten die 20 natürlich vorkommenden Aminosäuren sind. Die Verknüpfung der Aminosäuren zum Polypeptid geschieht unter Wasserabspaltung und Ausbildung einer Peptidbindung (s. Kap. 2). Polypeptide können sehr unterschiedliche Längen aufweisen, die zwischen drei und mehreren hundert Aminosäuren lang sein können. Die Sequenz, d.h. die Abfolge der Aminosäuren eines bestimmten Proteins, die auch als Primärstruktur bezeichnet wird, ist genetisch festgelegt. Sie wird während der Translation entsprechend der Informationen der mRNA aufgebaut.
UNLABELLED DNA chips have proven to be effective tools in detecting gene expression levels. Compared with DNA chips using complementary DNA as probes, oligonucleotide microarrays using oligonucleotides as probes have attracted great attention because of their well known advantages. The design of gene-specific probes for each target is essential to the development of oligonucleotide microarrays. We have previously reported the development of a probe design software termed Mprobe 1.0. Here, we present a new version of this software, termed Mprobe 2.0. Several new features are included in Mprobe 2.0. Firstly, a paradox-based sequence database management system has been developed and integrated into the software, which consequently allows interoperability with sequences in GenBank, EMBL, and FASTA formats. Secondly, in contrast to setting a fixed threshold for the secondary structure of probes in Mprobe 1.0 and other related software, Mprobe 2.0 employs a different method. After parameters such as GC type, probe melting temperature and GC contents have been evaluated, candidate probes are sorted by the free energy from high to low value, followed by specificity analysis. Thirdly, Mprobe 2.0 provides users with substantial parameter options in the visual mode. Mprobe 2.0 possesses an easier interface for users to manage sequences annotated in different formats and design the optimal probes for oligonucleotide microarrays and other applications. AVAILABILITY The program is free for non-commercial users and can be downloaded from the web page http://www.biosun.org.cn/mprobe/ CONTACT Wuju Li (wujuli@yahoo.com or liwj@nic.bmi.ac.cn).
This study presents a novel application, MultiPrimer, to assist users to design multiplex PCR primers. MultiPrimer adopts an algorithm based on a genetic algorithm and can efficiently solve the multi-objective optimisation problem. A match pattern model is proposed to speed up examination of the specificity constraint. MultiPrimer is able to find a set of primer pairs simultaneously for a set of gene family sequences and multiple targets for a single cDNA sequence. A public version of the MultiPrimer software is available from http://edith.cse.nsysu.edu.tw/new/software/MultiPrimer.htm.
UNLABELLED:EasyExonPrimer is a web-based software that automates the design of PCR primers to amplify exon sequences from genomic DNA. EasyExonPrimer is written in Perl and uses Primer3 to design PCR primers based on the genome builds and annotation databases available at the University of California, Santa Cruz (UCSC) Genome Browser database (http://genome.ucsc.edu/). It masks repeats and known single nucleotide polymorphism (SNP) sites in the genome and designs standardised primers using optimised conditions. Users can input genes by RefSeq mRNA ID, gene name or keyword. The primer design is optimised for large-scale resequencing of exons. For exons larger than 1 kb, the user has the option of breaking the exon sequence down into overlapping smaller fragments. All primer pairs are then verified using the In-Silico PCR software to test for uniqueness in the genome. We have designed >1000 pairs of primers for 90 genes; 95% of the primer pairs successfully amplified exon sequences under standard PCR conditions without requiring further optimisation.AVAILABILITY:EasyExonPrimer is available from http://129.43.22.27/~primer/. The source code is also available upon request.CONTACT:Xiaolin Wu (forestwu@mail.nih.gov).
UNLABELLED:With >1,000 prokaryotic genome sequencing projects ongoing or already finished, comprehensive comparative analysis of the gene content of these genomes has become viable. To allow for a meaningful comparative analysis, gene prediction of the various genomes should be as accurate as possible. It is clear that improving the state of genome annotation requires automated gene identification methods to cope with the influence of artifacts, such as genomic GC content. There is currently still room for improvement in the state of annotations. We present a web server and a database of high-quality gene predictions. The web server is a resource for gene identification in prokaryote genome sequences. It implements our previously described, accurate gene finding method REGANOR. We also provide novel gene predictions for 241 complete, or almost complete, prokaryotic genomes. We demonstrate how this resource can easily be utilised to identify promising candidates for currently missing genes from genome annotations with several examples. All data sets are available online.AVAILABILITY:The gene finding server is accessible via https://www.cebitec.uni-bielefeld.de/groups/brf/software/reganor/cgi-bin/reganor_upload.cgi. The server software is available with the GenDB genome annotation system (version 2.2.1 onwards) under the GNU general public license. The software can be downloaded from https://sourceforge.net/projects/gendb/. More information on installing GenDB and REGANOR and the system requirements can be found on the GenDB project page http://www.cebitec.uni-bielefeld.de/groups/brf/software/wiki/GenDBWiki/AdministratorDocumentation/GenDBInstallation
Adverse effects are exhibited by most drugs in current clinical practice, the causes for which are often not known. In this post genomic era, bioinformatics has the potential to address several issues in understanding the mechanism of drug action and in designing improved drugs. This study describes the analysis of the possible pharmacodynamic behaviour of antihistamines blocking the histamine H(2) receptor (H(2)-antihistamines), by adopting the basic tenets of a systems biology approach. The different components that could form an appropriate sub-system are identified, thus providing a system landscape. Docking and analysis of the chosen antihistamines into each of these components resulted in identifying histamine N-methyl transferase (HNMT) as a potential unintended target for H(2)-antihistamines. Correlation with experimental data available from the literature indicates the inhibition of HNMT to be a possible cause for the adverse effects exhibited by these drugs. Implications for design of safer H(2)-antihistamines are discussed. The method reported here has the potential for application as a general strategy in understanding drug effects.
UNLABELLED:Gene copy number variations occur both in normal cells and in numerous pathologies including cancer and developmental diseases. Array comparative genomic hybridisation (aCGH) is an emerging technology that allows detection of chromosomal gains and losses in a high-resolution format. When aCGH is performed on cDNA and oligonucleotide microarrays, the impact of DNA copy number on gene transcription profiles may be directly compared. We have created an online software tool, WebaCGH, that functions to (i) upload aCGH and gene transcription results from multiple experiments; (ii) identify significant aberrant regions using a local Z-score threshold in user-selected chromosomal segments subjected to smoothing with moving averages; and (iii) display results in a graphical format with full genome and individual chromosome views. In the individual chromosome display, data can be zoomed in/out in both dimensions (i.e. ratio and physical location) and plotted features can have 'mouse over' linking to outside databases to identify loci of interest. Uploaded data can be stored indefinitely for subsequent retrieval and analysis. WebaCGH was created as a Java-based web application using the open-source database MySQL.AVAILABILITY:WebaCGH is freely accessible at http://129.43.22.27/WebaCGH/welcome.htmCONTACT:Xiaolin Wu (forestwu@mail.nih.gov) or Ulises Urzúa (uurzua@med.uchile.cl).
UNLABELLED:TimeView is a MATLAB program that compares multiple temporal datasets from microarray experiments under two or more conditions, for example, temporal variation of cellular response upon exposure to different drugs. The current paucity of programs designed to efficiently compare and visualise gene expression profiles in such datasets led us to design TimeView, which also enhances data visualisation by plotting the expression profiles of a large number of genes on a single screen.AVAILABILITY:TimeView is available free of charge to all users at http://hugroup.cems.umn.edu/Research/Genomics/Timeview/timeview.htm. To use TimeView, users will require access to the commercial software MATLAB (version 6.5). A help document is available on the TimeView website.
UNLABELLED:OligoMatcher is a web-based tool for analysis and selection of unique oligonucleotide sequences for gene silencing by antisense oligonucleotides (ASOs) or small interfering RNA (siRNA). A specific BLAST server was built for analysing sequences of ASOs that target pre-mRNA in the cell nucleus. Tissue- and cell-specific expression data of potential cross-reactive genes are integrated in the OligoMatcher program, which allows biologists to select unique oligonucleotide sequences for their target genes in specific experimental systems.AVAILABILITY:The OligoMatcher web server is available at http://shelob.cs.iupui.edu:18081/oligomatch.php. The source code is freely available for non-profit use on request to the authors.CONTACT:Mathew Palakal (mpalakal@cs.iupui.edu) or Shuyu Li (li_shuyu_dan@lilly.com).
UNLABELLED The accurate computational prediction of T-cell epitopes can greatly reduce the experimental overhead implicit in candidate epitope identification within genomic sequences. In this article we present MHCPred 2.0, an enhanced version of our online, quantitative T-cell epitope prediction server. The previous version of MHCPred included mostly alleles from the human leukocyte antigen A (HLA-A) locus. In MHCPred 2.0, mouse models are added and computational constraints removed. Currently the server includes 11 human HLA class I, three human HLA class II, and three mouse class I models. Additionally, a binding model for the human transporter associated with antigen processing (TAP) is incorporated into the new MHCPred. A tool for the design of heteroclitic peptides is also included within the server. To refine the veracity of binding affinities prediction, a confidence percentage is also now calculated for each peptide predicted. AVAILABILITY As previously, MHCPred 2.0 is freely available at the URL http://www.jenner.ac.uk/MHCPred/ CONTACT Darren R. Flower (darren.flower@jenner.ac.uk).
DNA microarrays have been widely used to examine gene expression. The Affymetrix GeneChip® is one of the most commonly used platforms, employing DNA probes of 25 nucleotides designed to hybridise to different regions of target mRNA. The targeted region is often biased toward the 3′ end of mRNA, which can lead to biases in detection. A large number of mammalian genes can undergo alternative polyadenylation under different cellular conditions. Multiple polyadenylation sites can lead to variable transcripts with different hybridisation properties. Here, we surveyed probes on human, mouse and rat GeneChip® arrays and found that the detection of a significant proportion of mRNAs can potentially be affected by alternative polyadenylation. This could lead to inaccurate interpretation of GeneChip® data when the changes of expression values actually result from alternative use of polyadenylation sites.
