e-Fungi: a data resource for comparative analysis of fungal genomes.

BACKGROUND: The number of sequenced fungal genomes is ever increasing, with about 200 genomes already fully sequenced or in progress. Only a small percentage of those genomes have been comprehensively studied, for example using techniques from functional genomics. Comparative analysis has proven to be a useful strategy for enhancing our understanding of evolutionary biology and of the less well understood genomes. However, the data required for these analyses tends to be distributed in various heterogeneous data sources, making systematic comparative studies a cumbersome task. Furthermore, comparative analyses benefit from close integration of derived data sets that cluster genes or organisms in a way that eases the expression of requests that clarify points of similarity or difference between species. DESCRIPTION: To support systematic comparative analyses of fungal genomes we have developed the e-Fungi database, which integrates a variety of data for more than 30 fungal genomes. Publicly available genome data, functional annotations, and pathway information has been integrated into a single data repository and complemented with results of comparative analyses, such as MCL and OrthoMCL cluster analysis, and predictions of signaling proteins and the sub-cellular localisation of proteins. To access the data, a library of analysis tasks is available through a web interface. The analysis tasks are motivated by recent comparative genomics studies, and aim to support the study of evolutionary biology as well as community efforts for improving the annotation of genomes. Web services for each query are also available, enabling the tasks to be incorporated into workflows. CONCLUSION: The e-Fungi database provides fungal biologists with a resource for comparative studies of a large range of fungal genomes. Its analysis library supports the comparative study of genome data, functional annotation, and results of large scale analyses over all the genomes stored in the database. The database is accessible at http://www.e-fungi.org.uk, as is the WSDL for the web services.

A toolbox for predicting g-quadruplex formation and stability.

G-quadruplexes are four stranded nucleic acid structures formed around a core of guanines, arranged in squares with mutual hydrogen bonding. Many of these structures are highly thermally stable, especially in the presence of monovalent cations, such as those found under physiological conditions. Understanding of their physiological roles is expanding rapidly, and they have been implicated in regulating gene transcription and translation among other functions. We have built a community-focused website to act as a repository for the information that is now being developed. At its core, this site has a detailed database (QuadDB) of predicted G-quadruplexes in the human and other genomes, together with the predictive algorithm used to identify them. We also provide a QuadPredict server, which predicts thermal stability and acts as a repository for experimental data from all researchers. There are also a number of other data sources with computational predictions. We anticipate that the wide availability of this information will be of use both to researchers already active in this exciting field and to those who wish to investigate a particular gene hypothesis.

Stable G-quadruplexes are found outside nucleosome-bound regions.

Unusual DNA structures such as four-stranded G-quadruplexes have been found to form in vivo and to play regulatory roles. However, since DNA is normally present as chromatin, with the double helix wrapped around histone proteins, it is unclear how a G-quadruplex could form in such a region. Here, we show that regulatory G-quadruplexes found upstream of transcription start sites are in fact located in a region depleted of nucleosomes, and that in general in both Caenorhabditis elegans and humans, stable G-quadruplexes are located outside nucleosome-bound regions, hence making it easier for them to form in vivo.

Function and targeting of G-quadruplexes.

Guanine-rich sequences of DNA and RNA may fold in vitro and in vivo into G-quadruplexes, four-stranded helical structures held together by a guanine core. G-quadruplexes have various biological functions, including inhibition of telomerase and the regulation of gene transcription and translation, and have become an active target for drug development, particularly for novel anticancer therapies. The physiological functions of G-quadruplexes are discussed in this review and the current knowledge of G-quadruplex ligand and drug development is outlined.

Comparative genome analysis of filamentous fungi reveals gene family expansions associated with fungal pathogenesis.

Fungi and oomycetes are the causal agents of many of the most serious diseases of plants. Here we report a detailed comparative analysis of the genome sequences of thirty-six species of fungi and oomycetes, including seven plant pathogenic species, that aims to explore the common genetic features associated with plant disease-causing species. The predicted translational products of each genome have been clustered into groups of potential orthologues using Markov Chain Clustering and the data integrated into the e-Fungi object-oriented data warehouse (http://www.e-fungi.org.uk/). Analysis of the species distribution of members of these clusters has identified proteins that are specific to filamentous fungal species and a group of proteins found only in plant pathogens. By comparing the gene inventories of filamentous, ascomycetous phytopathogenic and free-living species of fungi, we have identified a set of gene families that appear to have expanded during the evolution of phytopathogens and may therefore serve important roles in plant disease. We have also characterised the predicted set of secreted proteins encoded by each genome and identified a set of protein families which are significantly over-represented in the secretomes of plant pathogenic fungi, including putative effector proteins that might perturb host cell biology during plant infection. The results demonstrate the potential of comparative genome analysis for exploring the evolution of eukaryotic microbial pathogenesis.

Comparative genome analysis across a kingdom of eukaryotic organisms: specialization and diversification in the fungi.

The recent proliferation of genome sequencing in diverse fungal species has provided the first opportunity for comparative genome analysis across a eukaryotic kingdom. Here, we report a comparative study of 34 complete fungal genome sequences, representing a broad diversity of Ascomycete, Basidiomycete, and Zygomycete species. We have clustered all predicted protein-encoding gene sequences from these species to provide a means of investigating gene innovations, gene family expansions, protein family diversification, and the conservation of essential gene functions-empirically determined in Saccharomyces cerevisiae-among the fungi. The results are presented with reference to a phylogeny of the 34 fungal species, based on 29 universally conserved protein-encoding gene sequences. We contrast this phylogeny with one based on gene presence and absence and show that, while the two phylogenies are largely in agreement, there are differences in the positioning of some species. We have investigated levels of gene duplication and demonstrate that this varies greatly between fungal species, although there are instances of coduplication in distantly related fungi. We have also investigated the extent of orthology for protein families and demonstrate unexpectedly high levels of diversity among genes involved in lipid metabolism. These analyses have been collated in the e-Fungi data warehouse, providing an online resource for comparative genomic analysis of the fungi.