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Background: The success of the CRISPR/Cas9 genome editing technique depends on the choice of the guide RNA sequence, which is facilitated by various websites. Despite the importance and popularity of these algorithms, it is unclear to which extent their predictions are in agreement with actual measurements., Results: We conduct the first independent evaluation of CRISPR/Cas9 predictions. To this end, we collect data from eight SpCas9 off-target studies and compare them with the sites predicted by popular algorithms. We identify problems in one implementation but found that sequence-based off-target predictions are very reliable, identifying most off-targets with mutation rates superior to 0.1 %, while the number of false positives can be largely reduced with a cutoff on the off-target score. We also evaluate on-target efficiency prediction algorithms against available datasets. The correlation between the predictions and the guide activity varied considerably, especially for zebrafish. Together with novel data from our labs, we find that the optimal on-target efficiency prediction model strongly depends on whether the guide RNA is expressed from a U6 promoter or transcribed in vitro. We further demonstrate that the best predictions can significantly reduce the time spent on guide screening., Conclusions: To make these guidelines easily accessible to anyone planning a CRISPR genome editing experiment, we built a new website ( http://crispor.org ) that predicts off-targets and helps select and clone efficient guide sequences for more than 120 genomes using different Cas9 proteins and the eight efficiency scoring systems evaluated here.

The CRISPR-Cas revolution is taking place in virtually all fields of life sciences. Harnessing DNA cleavage with the CRISPR-Cas9 system of Streptococcus pyogenes has proven to be extraordinarily simple and efficient, relying only on the design of a synthetic single guide RNA (sgRNA) and its co-expression with Cas9. Here, we review the progress in the design of sgRNA from the original dual RNA guide for S. pyogenes and Staphylococcus aureus Cas9 (SpCas9 and SaCas9). New assays for genome-wide identification of off-targets have provided important insights into the issue of cleavage specificity in vivo. At the same time, the on-target activity of thousands of guides has been determined. These data have led to numerous online tools that facilitate the selection of guide RNAs in target sequences. It appears that for most basic research applications, cleavage activity can be maximized and off-targets minimized by carefully choosing guide RNAs based on computational predictions. Moreover, recent studies of Cas proteins have further improved the flexibility and precision of the CRISPR-Cas toolkit for genome editing. Inspired by the crystal structure of the complex of sgRNA-SpCas9 bound to target DNA, several variants of SpCas9 have recently been engineered, either with novel protospacer adjacent motifs (PAMs) or with drastically reduced off-targets. Novel Cas9 and Cas9-like proteins called Cpf1 have also been characterized from other bacteria and will benefit from the insights obtained from SpCas9. Genome editing with CRISPR-Cas9 may also progress with better understanding and control of cellular DNA repair pathways activated after Cas9-induced DNA cleavage., (Copyright © 2016 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.)

Background: Patients with LIS1-associated classic lissencephaly typically present with severe psychomotor retardation and drug-resistant epilepsy within the first year., Aim: To analyze the epileptogenic phenotype and response to antiepileptic therapy in LIS1-associated classic lissencephaly., Method: Retrospective evaluation of 22 patients (8 months-24 years) with genetically and radiologically confirmed LIS1-associated classic lissencephaly in 16 study centers., Results: All patients in our cohort developed drug-resistant epilepsy. In 82% onset of seizures was noted within the first six months of life, most frequently with infantile spasms. Later in infancy the epileptogentic phenotype became more variable and included different forms of focal seizures as well generalized as tonic-clonic seizures, with generalized tonic-clonic seizures being the predominant type. Lamotrigine and valproate were rated most successful with good or partial response rates in 88-100% of the patients. Both were evaluated significantly better than levetiracetam (p<0.05) and sulthiame (p<0.01) in the neuropediatric assessment and better than levetiracetam, sulthiame (p<0.05) and topiramate (p<0.01) in the family survey. Phenobarbital and vigabatrin achieved good or partial response in 62-83% of the patients., Conclusion: Our findings suggest that patients with LIS1-associated lissencephaly might benefit most from lamotrigine, valproate, vigabatrin or phenobarbital., (Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

For the past 15 years, the UCSC Genome Browser (http://genome.ucsc.edu/) has served the international research community by offering an integrated platform for viewing and analyzing information from a large database of genome assemblies and their associated annotations. The UCSC Genome Browser has been under continuous development since its inception with new data sets and software features added frequently. Some release highlights of this year include new and updated genome browsers for various assemblies, including bonobo and zebrafish; new gene annotation sets; improvements to track and assembly hub support; and a new interactive tool, the "Data Integrator", for intersecting data from multiple tracks. We have greatly expanded the data sets available on the most recent human assembly, hg38/GRCh38, to include updated gene prediction sets from GENCODE, more phenotype- and disease-associated variants from ClinVar and ClinGen, more genomic regulatory data, and a new multiple genome alignment., (© The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Unlabelled: Genome Browser in a Box (GBiB) is a small virtual machine version of the popular University of California Santa Cruz (UCSC) Genome Browser that can be run on a researcher's own computer. Once GBiB is installed, a standard web browser is used to access the virtual server and add personal data files from the local hard disk. Annotation data are loaded on demand through the Internet from UCSC or can be downloaded to the local computer for faster access., Availability and Implementation: Software downloads and installation instructions are freely available for non-commercial use at https://genome-store.ucsc.edu/. GBiB requires the installation of open-source software VirtualBox, available for all major operating systems, and the UCSC Genome Browser, which is open source and free for non-commercial use. Commercial use of GBiB and the Genome Browser requires a license (http://genome.ucsc.edu/license/)., (© The Author 2014. Published by Oxford University Press.)

The gene regulatory network (GRN) that supports neural stem cell (NS cell) self-renewal has so far been poorly characterized. Knowledge of the central transcription factors (TFs), the noncoding gene regulatory regions that they bind to, and the genes whose expression they modulate will be crucial in unlocking the full therapeutic potential of these cells. Here, we use DNase-seq in combination with analysis of histone modifications to identify multiple classes of epigenetically and functionally distinct cis-regulatory elements (CREs). Through motif analysis and ChIP-seq, we identify several of the crucial TF regulators of NS cells. At the core of the network are TFs of the basic helix-loop-helix (bHLH), nuclear factor I (NFI), SOX, and FOX families, with CREs often densely bound by several of these different TFs. We use machine learning to highlight several crucial regulatory features of the network that underpin NS cell self-renewal and multipotency. We validate our predictions by functional analysis of the bHLH TF OLIG2. This TF makes an important contribution to NS cell self-renewal by concurrently activating pro-proliferation genes and preventing the untimely activation of genes promoting neuronal differentiation and stem cell quiescence., (© 2015 Mateo et al.; Published by Cold Spring Harbor Laboratory Press.)

Launched in 2001 to showcase the draft human genome assembly, the UCSC Genome Browser database (http://genome.ucsc.edu) and associated tools continue to grow, providing a comprehensive resource of genome assemblies and annotations to scientists and students worldwide. Highlights of the past year include the release of a browser for the first new human genome reference assembly in 4 years in December 2013 (GRCh38, UCSC hg38), a watershed comparative genomics annotation (100-species multiple alignment and conservation) and a novel distribution mechanism for the browser (GBiB: Genome Browser in a Box). We created browsers for new species (Chinese hamster, elephant shark, minke whale), 'mined the web' for DNA sequences and expanded the browser display with stacked color graphs and region highlighting. As our user community increasingly adopts the UCSC track hub and assembly hub representations for sharing large-scale genomic annotation data sets and genome sequencing projects, our menu of public data hubs has tripled., (© The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Throughout evolution primate genomes have been modified by waves of retrotransposon insertions. For each wave, the host eventually finds a way to repress retrotransposon transcription and prevent further insertions. In mouse embryonic stem cells, transcriptional silencing of retrotransposons requires KAP1 (also known as TRIM28) and its repressive complex, which can be recruited to target sites by KRAB zinc-finger (KZNF) proteins such as murine-specific ZFP809 which binds to integrated murine leukaemia virus DNA elements and recruits KAP1 to repress them. KZNF genes are one of the fastest growing gene families in primates and this expansion is hypothesized to enable primates to respond to newly emerged retrotransposons. However, the identity of KZNF genes battling retrotransposons currently active in the human genome, such as SINE-VNTR-Alu (SVA) and long interspersed nuclear element 1 (L1), is unknown. Here we show that two primate-specific KZNF genes rapidly evolved to repress these two distinct retrotransposon families shortly after they began to spread in our ancestral genome. ZNF91 underwent a series of structural changes 8-12 million years ago that enabled it to repress SVA elements. ZNF93 evolved earlier to repress the primate L1 lineage until ∼12.5 million years ago when the L1PA3-subfamily of retrotransposons escaped ZNF93's restriction through the removal of the ZNF93-binding site. Our data support a model where KZNF gene expansion limits the activity of newly emerged retrotransposon classes, and this is followed by mutations in these retrotransposons to evade repression, a cycle of events that could explain the rapid expansion of lineage-specific KZNF genes.

Background: With the Ebola epidemic raging out of control in West Africa, there has been a flurry of research into the Ebola virus, resulting in the generation of much genomic data., Methods: In response to the clear need for tools that integrate multiple strands of research around molecular sequences, we have created the University of California Santa Cruz (UCSC) Ebola Genome Browser, an adaptation of our popular UCSC Genome Browser web tool, which can be used to view the Ebola virus genome sequence from GenBank and nearly 30 annotation tracks generated by mapping external data to the reference sequence. Significant annotations include a multiple alignment comprising 102 Ebola genomes from the current outbreak, 56 from previous outbreaks, and 2 Marburg genomes as an outgroup; a gene track curated by NCBI; protein annotations curated by UniProt and antibody-binding epitopes curated by IEDB. We have extended the Genome Browser's multiple alignment color-coding scheme to distinguish mutations resulting from non-synonymous coding changes, synonymous changes, or changes in untranslated regions., Discussion: Our Ebola Genome portal at http://genome.ucsc.edu/ebolaPortal/ links to the Ebola virus Genome Browser and an aggregate of useful information, including a collection of Ebola antibodies we are curating.

This study describes a facile and high yielding route to two series of polymethacrylates inspired by the naturally occurring, tryptophan-rich cationic antimicrobial polymers. Appropriate optimization of indole content within each gave rise to polymers with high potency against Staphylococcus epidermidis (e.g., PGI-3 minimum inhibitory concentration (MIC) = 12 μg/mL) and the methicillin-resistant strain of Staphylococcus aureus (e.g., PGI-3 MIC = 47 μg/mL) with minimal toxicity toward human red blood cells. Future work will be directed toward understanding the cooperative roles that the cationic and indole pendant groups have for the mechanism of these polymers.

This study compares three common laboratory methods, size-exclusion chromatography (SEC), (1)H nuclear magnetic resonance (NMR), and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), to determine the molecular weight of oligomeric cationic copolymers. The potential bias for each method was examined across a series of polymers that varied in molecular weight and cationic character (both choice of cation (amine versus guanidine) and relative proportion present). SEC was found to be the least accurate, overestimating Mn by an average of 140%, owing to the lack of appropriate cationic standards available, and the complexity involved in estimating the hydrodynamic volume of copolymers. MALDI-TOF approximated Mn well for the highly monodisperse (Đ < 1.1), low molecular weight (degree of polymerization (DP) <50) species but appeared unsuitable for the largest polymers in the series due to the mass bias associated with the technique. (1)H NMR was found to most accurately estimate Mn in this study, differing to theoretical values by only 5.2%. (1)H NMR end-group analysis is therefore an inexpensive and facile, primary quantitative method to estimate the molecular weight of oliogomeric cationic polymethacrylates if suitably distinct end-groups signals are present in the spectrum.

The University of California Santa Cruz (UCSC) Genome Browser (http://genome.ucsc.edu) offers online public access to a growing database of genomic sequence and annotations for a large collection of organisms, primarily vertebrates, with an emphasis on the human and mouse genomes. The Browser's web-based tools provide an integrated environment for visualizing, comparing, analysing and sharing both publicly available and user-generated genomic data sets. As of September 2013, the database contained genomic sequence and a basic set of annotation 'tracks' for ∼90 organisms. Significant new annotations include a 60-species multiple alignment conservation track on the mouse, updated UCSC Genes tracks for human and mouse, and several new sets of variation and ENCODE data. New software tools include a Variant Annotation Integrator that returns predicted functional effects of a set of variants uploaded as a custom track, an extension to UCSC Genes that displays haplotype alleles for protein-coding genes and an expansion of data hubs that includes the capability to display remotely hosted user-provided assembly sequence in addition to annotation data. To improve European access, we have added a Genome Browser mirror (http://genome-euro.ucsc.edu) hosted at Bielefeld University in Germany.

We have synthesized a series of copolymers containing both positively charged (amine, guanidine) and hydrophobic side chains (amphiphilic antimicrobial peptide mimics). To investigate the structure-activity relationships of these polymers, low polydispersity polymethacrylates of varying but uniform molecular weight and composition were synthesized, using a reversible addition-fragmentation chain transfer (RAFT) approach. In a facile second reaction, pendant amine groups were converted to guanidines, allowing for direct comparison of cation structure on activity and toxicity. The guanidine copolymers were much more active against Staphylococcus epidermidis and Candida albicans compared to the amine analogues. Activity against Staphylococcus epidermidis in the presence of fetal bovine serum was only maintained for guanidine copolymers. Selectivity for bacterial over mammalian cells was assessed using hemolytic and hemagglutination toxicity assays. Guanidine copolymers of low to moderate molecular weight and hydrophobicity had high antimicrobial activity with low toxicity. Optimum properties appear to be a balance between charge density, hydrophobic character, and polymer chain length. In conclusion, a suite of guanidine copolymers has been identified that represent a new class of antimicrobial polymers with high potency and low toxicity.

The University of California Santa Cruz (UCSC) Genome Browser (http://genome.ucsc.edu) offers online public access to a growing database of genomic sequence and annotations for a wide variety of organisms. The Browser is an integrated tool set for visualizing, comparing, analysing and sharing both publicly available and user-generated genomic datasets. As of September 2012, genomic sequence and a basic set of annotation 'tracks' are provided for 63 organisms, including 26 mammals, 13 non-mammal vertebrates, 3 invertebrate deuterostomes, 13 insects, 6 worms, yeast and sea hare. In the past year 19 new genome assemblies have been added, and we anticipate releasing another 28 in early 2013. Further, a large number of annotation tracks have been either added, updated by contributors or remapped to the latest human reference genome. Among these are an updated UCSC Genes track for human and mouse assemblies. We have also introduced several features to improve usability, including new navigation menus. This article provides an update to the UCSC Genome Browser database, which has been previously featured in the Database issue of this journal.

The complex, partially redundant gene regulatory architecture underlying vertebrate heart formation has been difficult to characterize. Here, we dissect the primary cardiac gene regulatory network in the invertebrate chordate, Ciona intestinalis. The Ciona heart progenitor lineage is first specified by Fibroblast Growth Factor/Map Kinase (FGF/MapK) activation of the transcription factor Ets1/2 (Ets). Through microarray analysis of sorted heart progenitor cells, we identified the complete set of primary genes upregulated by FGF/Ets shortly after heart progenitor emergence. Combinatorial sequence analysis of these co-regulated genes generated a hypothetical regulatory code consisting of Ets binding sites associated with a specific co-motif, ATTA. Through extensive reporter analysis, we confirmed the functional importance of the ATTA co-motif in primary heart progenitor gene regulation. We then used the Ets/ATTA combination motif to successfully predict a number of additional heart progenitor gene regulatory elements, including an intronic element driving expression of the core conserved cardiac transcription factor, GATAa. This work significantly advances our understanding of the Ciona heart gene network. Furthermore, this work has begun to elucidate the precise regulatory architecture underlying the conserved, primary role of FGF/Ets in chordate heart lineage specification., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Summary: Identifying mentions of named entities, such as genes or diseases, and normalizing them to database identifiers have become an important step in many text and data mining pipelines. Despite this need, very few entity normalization systems are publicly available as source code or web services for biomedical text mining. Here we present the Gnat Java library for text retrieval, named entity recognition, and normalization of gene and protein mentions in biomedical text. The library can be used as a component to be integrated with other text-mining systems, as a framework to add user-specific extensions, and as an efficient stand-alone application for the identification of gene and protein names for data analysis. On the BioCreative III test data, the current version of Gnat achieves a Tap-20 score of 0.1987., Availability: The library and web services are implemented in Java and the sources are available from http://gnat.sourceforge.net., Contact: jorg.hakenberg@roche.com.

Motivation: Increasing rates of publication and DNA sequencing make the problem of finding relevant articles for a particular gene or genomic region more challenging than ever. Existing text-mining approaches focus on finding gene names or identifiers in English text. These are often not unique and do not identify the exact genomic location of a study., Results: Here, we report the results of a novel text-mining approach that extracts DNA sequences from biomedical articles and automatically maps them to genomic databases. We find that ∼20% of open access articles in PubMed central (PMC) have extractable DNA sequences that can be accurately mapped to the correct gene (91%) and genome (96%). We illustrate the utility of data extracted by text2genome from more than 150 000 PMC articles for the interpretation of ChIP-seq data and the design of quantitative reverse transcriptase (RT)-PCR experiments., Conclusion: Our approach links articles to genes and organisms without relying on gene names or identifiers. It also produces genome annotation tracks of the biomedical literature, thereby allowing researchers to use the power of modern genome browsers to access and analyze publications in the context of genomic data., Availability and Implementation: Source code is available under a BSD license from http://sourceforge.net/projects/text2genome/ and results can be browsed and downloaded at http://text2genome.org.

A major prerequisite for the investigation of tissue-specific processes is the identification of cis-regulatory elements. No generally applicable technique is available to distinguish them from any other type of genomic non-coding sequence. Therefore, researchers often have to identify these elements by elaborate in vivo screens, testing individual regions until the right one is found. Here, based on many examples from the literature, we summarize how functional enhancers have been isolated from other elements in the genome and how they have been characterized in transgenic animals. Covering computational and experimental studies, we provide an overview of the global properties of cis-regulatory elements, like their specific interactions with promoters and target gene distances. We describe conserved non-coding elements (CNEs) and their internal structure, nucleotide composition, binding site clustering and overlap, with a special focus on developmental enhancers. Conflicting data and unresolved questions on the nature of these elements are highlighted. Our comprehensive overview of the experimental shortcuts that have been found in the different model organism communities and the new field of high-throughput assays should help during the preparation phase of a screen for enhancers. The review is accompanied by a list of general guidelines for such a project., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Background: The last two decades have witnessed a dramatic acceleration in the production of genomic sequence information and publication of biomedical articles. Despite the fact that genome sequence data and publications are two of the most heavily relied-upon sources of information for many biologists, very little effort has been made to systematically integrate data from genomic sequences directly with the biological literature. For a limited number of model organisms dedicated teams manually curate publications about genes; however for species with no such dedicated staff many thousands of articles are never mapped to genes or genomic regions., Methodology/principal Findings: To overcome the lack of integration between genomic data and biological literature, we have developed pubmed2ensembl (http://www.pubmed2ensembl.org), an extension to the BioMart system that links over 2,000,000 articles in PubMed to nearly 150,000 genes in Ensembl from 50 species. We use several sources of curated (e.g., Entrez Gene) and automatically generated (e.g., gene names extracted through text-mining on MEDLINE records) sources of gene-publication links, allowing users to filter and combine different data sources to suit their individual needs for information extraction and biological discovery. In addition to extending the Ensembl BioMart database to include published information on genes, we also implemented a scripting language for automated BioMart construction and a novel BioMart interface that allows text-based queries to be performed against PubMed and PubMed Central documents in conjunction with constraints on genomic features. Finally, we illustrate the potential of pubmed2ensembl through typical use cases that involve integrated queries across the biomedical literature and genomic data., Conclusion/significance: By allowing biologists to find the relevant literature on specific genomic regions or sets of functionally related genes more easily, pubmed2ensembl offers a much-needed genome informatics inspired solution to accessing the ever-increasing biomedical literature.

One of the striking findings of comparative developmental genetics was that expression patterns of core transcription factors are extraordinarily conserved in bilaterians. However, it remains unclear whether cis-regulatory elements of their target genes also exhibit common signatures associated with conserved embryonic fields. To address this question, we focused on genes that are active in the anterior neuroectoderm and non-neural ectoderm of the ascidian Ciona intestinalis. Following the dissection of a prototypic anterior placodal enhancer, we searched all genomic conserved non-coding elements for duplicated motifs around genes showing anterior neuroectodermal expression. Strikingly, we identified an over-represented pentamer motif corresponding to the binding site of the homeodomain protein OTX, which plays a pivotal role in the anterior development of all bilaterian species. Using an in vivo reporter gene assay, we observed that 10 of 23 candidate cis-regulatory elements containing duplicated OTX motifs are active in the anterior neuroectoderm, thus showing that this cis-regulatory signature is predictive of neuroectodermal enhancers. These results show that a common cis-regulatory signature corresponding to K50-Paired homeodomain transcription factors is found in non-coding sequences flanking anterior neuroectodermal genes in chordate embryos. Thus, field-specific selector genes impose architectural constraints in the form of combinations of short tags on their target enhancers. This could account for the strong evolutionary conservation of the regulatory elements controlling field-specific selector genes responsible for body plan formation., Competing Interests: LC joined the faculty of New York University after the review process had commenced.

Anteroposterior patterning of the ectoderm in the invertebrate chordate Ciona intestinalis first relies on key zygotic activators, such as FoxA, and later on the coordinated responses to inducing signals from the underlying mesendoderm. Here, we focus on a mechanism of coordination of these responses by looking at the cis-regulatory logics of Ci-Rora and Ci-Rorb, which are coding for putative non-canonical transmembrane Wnt receptors, and are present in tandem along the C. intestinalis chromosome 08q. We showed that during cleavage stages, both Ci-Rora and Ci-Rorb genes are initially expressed in all blastomeres of the anterior ectoderm (a-line), as sFRP1/5 (Lamy, C., Rothbächer, U., Caillol, D., Lemaire, P., 2006. Ci-FoxA-a is the earliest zygotic determinant of the ascidian anterior ectoderm and directly activates Ci-sFRP1/5. Development 133, 2835-2844.). We then carried out a functional analysis of cis-regulatory regions and showed that both genes have elements enriched in Ci-FoxA-a binding sites. We dissected one of these early enhancers, and showed that it is directly activated by Ci-FoxA-a, as one sFRP1/5 cis-regulatory element. We also showed that although FoxA binding sites are abundant in genomes, dense clusters of these sites are found upstream from very few genes, and have a high predictive value of a-line expression. These data indicate an important role for FoxA in anterior specification, via the transcriptional regulation of target genes belonging to various signalling pathways.

Background: Decoding transcriptional regulatory networks and the genomic cis-regulatory logic implemented in their control nodes is a fundamental challenge in genome biology. High-throughput computational and experimental analyses of regulatory networks and sequences rely heavily on positive control data from prior small-scale experiments, but the vast majority of previously discovered regulatory data remains locked in the biomedical literature., Results: We develop text-mining strategies to identify relevant publications and extract sequence information to assist the regulatory annotation process. Using a vector space model to identify Medline abstracts from papers likely to have high cis-regulatory content, we demonstrate that document relevance ranking can assist the curation of transcriptional regulatory networks and estimate that, minimally, 30,000 papers harbor unannotated cis-regulatory data. In addition, we show that DNA sequences can be extracted from primary text with high cis-regulatory content and mapped to genome sequences as a means of identifying the location, organism and target gene information that is critical to the cis-regulatory annotation process., Conclusion: Our results demonstrate that text-mining technologies can be successfully integrated with genome annotation systems, thereby increasing the availability of annotated cis-regulatory data needed to catalyze advances in the field of gene regulation.

ORegAnno is an open-source, open-access database and literature curation system for community-based annotation of experimentally identified DNA regulatory regions, transcription factor binding sites and regulatory variants. The current release comprises 30 145 records curated from 922 publications and describing regulatory sequences for over 3853 genes and 465 transcription factors from 19 species. A new feature called the 'publication queue' allows users to input relevant papers from scientific literature as targets for annotation. The queue contains 4438 gene regulation papers entered by experts and another 54 351 identified by text-mining methods. Users can enter or 'check out' papers from the queue for manual curation using a series of user-friendly annotation pages. A typical record entry consists of species, sequence type, sequence, target gene, binding factor, experimental outcome and one or more lines of experimental evidence. An evidence ontology was developed to describe and categorize these experiments. Records are cross-referenced to Ensembl or Entrez gene identifiers, PubMed and dbSNP and can be visualized in the Ensembl or UCSC genome browsers. All data are freely available through search pages, XML data dumps or web services at: http://www.oreganno.org.

With the availability of an increasing number of whole genome sequences in chordates, exhaustive comparisons of multigene families become feasible. Relationships of orthology/paralogy can not only be inferred from sequence similarity but also by comparing synteny conservation on chromosomes. More accurate scenarios for gene and expression domain gain or loss can now be proposed. Here, we take benefit from the recent release of the medaka (Oryzias latipes) genome to analyse the orthology relationships and expression patterns of the three different sub-families of the pitx homeobox genes belonging to the paired class. They are involved in a wide variety of developmental processes and have pleiotropic expression patterns, especially in the case of the pitx2 sub-family. The emerging picture is a strong conservation of expression domains, suggesting that most functions have been present in the common ancestor of actinopterygians and sarcopterygians. Almost all pitx genes are expressed in anterior placodes in all species studied so far, including medaka. It has previously been shown that in mammals, pitx1 and 2 are expressed in the pituitary. Interestingly we demonstrate here that only pitx3 is expressed in medaka pituitary. It will be interesting to analyze what are the corresponding changes in the regulatory elements of pitx genes.

A novel class of biofunctional silole nanocrystals with the potential to create highly sensitive immunoassay was firstly demonstrated. Biolabels were constructed by encapsulating nanocrystalline hexaphenylsilole [Ph2Si(CPh)4HPS] within ultrathin polyelectrolyte layers via the layer-by-layer (LbL) technique that provided an "interface" for the attachment of antibodies. A high ratio of fluorescent dyes to biomolecules (F/P ratio; 2.4 x 10(3)) was achieved without self-quenching problem. The aggregation-induced emission (AIE) feature offered silole biolabels the sensitivity 40- to 140-fold higher than that of a start-of-the-art immunoassay using directly fluorescent-labeled antibodies.